car slower after carb change

[69chargerR/T]

This is what I have, 69 charger with 440 30 over, TRW flat top pistons, stock 906 heads, mp 284/484 cam, hooker comp 1 7/8 headers,eddy RPM intake, flowmaster 3 inch exhaust, TCI street fighter auto trans,TCI 11" breakaway converter stall is around 2200 to 2500, 3.91 sure grip, mp electronic ignition. I'm on my 4th carb, carb #1 eddy 750 performer had off idle stumble good top end, didn't like, #2 carb holley 3310 this carb ran pretty good but, had what I think was a lean off idle backfire in carb, I tried bigger discharge nozzles #s 25,28,31 no change. Tried different pump cams, adjusted pump adjustment spring no change. Thought maybe its the carb, carb #3 holley 770 srteet avenger, carb had same problem carb came with # 25 pump nozzle changed to #31 still backfires but not as bad. Only backfires when you step on it hard from dead stop, if you put your foot on brake bring RPM up to say 1500 or so mash it to the floor no stumble at all and smokes the tires hit second gear still smoking the tires So I left it like that car ran pretty good would pull nice right up to 5000 RPM. Thinking the car could be quicker put lighter spring in secondary, car felt like it pulls even harder So, I think maybe 750dp would make the car quicker and pull a little harder,and get rid of my backfire problem, carb #4 holley 750dp with 4 corner idle got carb off ebay carb only 2 years old carb didn't have stock jets in it so I got stock jets 71s front 80s rear, took carb apart you could tell the carb had almost no miles on it it was super clean looked like  brand new in side!!! Put carb on got it all adjusted, car feels slower, doesn't seem to pull as hard as the 770 avenger and still backfires
I have tried re curving the distributor changed timing settings, no change car still feels slower Car would always chirp the tires on a full throttle run when shifting from first to second, and pull harder with the avenger, also the 750dp also backfires when you hit the throttle hard, and I put a #35 pump nozzle in it and it still backfires   I'm out of ideas, only think I can think of is the 750dp secondary is to rich, the 770 avenger has #72s jets front #75s rear I was thinking of dropping the 750dp rear jets from #80s to #77s or #75s. that seems to be the only difference between the 770 and 750dp is the secondary jetting. As for the hard off idle backfire I don't know if the mp cam is giving me this problem, the carb, timing, I've tried every thing I can think of I do want to change the cam, I just hope I don't have the same problems with the backfire, as for my power loss I think rejetting the 750dp will help. I'll take any ideas out there I need help !!!!!! I'm thinking of putting the 770 avenger back on cause I think car had more power with that carb but I will still have the what I think is lean hard off idle backfire that I don't know what to do to to fix I thought that the 750dp because it had the mechanical secondaries would give me that head jerking throttle response but thats not the case, I'm out of tuning ideas


                                                                                Thanks, Alan

                                                                           






   

[firefighter3931]

Alan, Make sure the secondary linkage isn't binding up. I've seen a few double pumpers that weren't opening up completely. Also check to make sure your throttle linkage is operating properly and the cable is adjusted for wide open. There is a specific adapter for mopar engines that needs to be used when installing holley carburators.

http://static.summitracing.com/global/images/instructions/hly-r10167%282%291.pdf

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D20%2D7&N=700+4294925239+4294839063+4294844433+115&autoview=sku



Ron

[69chargerR/T]

Alan, Make sure the secondary linkage isn't binding up. I've seen a few double pumpers that weren't opening up completely. Also check to make sure your throttle linkage is operating properly and the cable is adjusted for wide open. There is a specific adapter for mopar engines that needs to be used when installing holley carburators.

http://static.summitracing.com/global/images/instructions/hly-r10167%282%291.pdf

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D20%2D7&N=700+4294925239+4294839063+4294844433+115&autoview=sku



Ron

Ron, checked my throttle linkage, cable is pulling throttle full open, I am using throttle adapter. I opened the throttle by hand to check throttle plates, when holding throttle wide open the primary throttle plates are strait up and down, the secondary plates are not completely strait up and down. They are almost strait up and down but not quite,would this make a big difference if they are not fully strait up and down The only way I see to fix this is to bend the secondary link,but wouldn't that make the secondary open sooner,would that be a problem
Also what do you think about my backfire in carb when I hit the throttle hard from a dead stop,I think its a lean off idle problem.

                                                                         Thanks, Alan



   

[firefighter3931]

Alan, bend the link and make sure the secondary throttle plates are vertical....it will make a difference. I'm assuming you checked the float levels ? It does sound like a lean off idle condition. Make sure the accelerator pump is adjusted properly and working if you haven't looked at that allready.

What does the timing curve look like ? How much advance at idle ? How do the plugs look ?

I'm also wondering about a possible vacuum leak since the backfire condition existed with both carbs. Try partially covering the primary venturies to see if it's drawing air from another source. Hook up a vacuum guage and see what you've got.


Ron

[69chargerR/T]

Alan, bend the link and make sure the secondary throttle plates are vertical....it will make a difference. I'm assuming you checked the float levels ? It does sound like a lean off idle condition. Make sure the accelerator pump is adjusted properly and working if you haven't looked at that allready.

What does the timing curve look like ? How much advance at idle ? How do the plugs look ?



Ron

Ron, I will try bending the secondary link to get the throttle plates strait up and down :2thumbs:As for the accelerator pump I tried adjusting the pump spring and bolt adjustment no change with backfire problem,put #35 pump nozzle in it I think that helped a little not much. I do have a #37 nozzle I might try or thinking maybe trying a tube type nozzle. As for timing I have initial at 19* total 36* all in at 2800-3000,the mp dizzy came with two pink springs that are very light total was all in at 1700-2000,so I changed to a two stage advance curve using the loose purple spring and the orange spring. I have the idle set at 850 RPM advance starts at about 1000 RPM. All the carbs I had on this car did the same thing the 3310 the 770 avenger and the 750dp the 3310 I tried nozzles, pump spring adjustments, pump cams with litle or no change I've read that mp cams can be tricky to tune, I am usually pretty good at tuning but this is driving me crazy Car runs good as long as I don't mash it to the floor really quick, If I bring the RPMS up to say 1500 and mash it to the floor car takes off and smokes the tires Thats why I'm thinking of changing the cam, probably to the voodoo 60303 and hope this problem is gone !!!!!!!!!!!!!



   
                                                                 Thanks, Alan


       

[firefighter3931]

Alan, the timing looks fine....the initial and total are right where they should be with that combo. 

The motor is telling you it wants more fuel at the transisition. It's either the pump shot or a jetting issue. Have you tried jetting up on the primaries ? Have a look at the secondary accelerator pump adjustment as well. From your description it seems that once the engine is running on the main circuit (1500 rpm) there is no backfire which is good news. The problem lies in the transition from idle to WOT. Based on your latest report i don't think it's a vacuum leak....keep tuning bud ! 


Ron

[69chargerR/T]

Alan, bend the link and make sure the secondary throttle plates are vertical....it will make a difference. I'm assuming you checked the float levels ? It does sound like a lean off idle condition. Make sure the accelerator pump is adjusted properly and working if you haven't looked at that allready.

What does the timing curve look like ? How much advance at idle ? How do the plugs look ?

I'm also wondering about a possible vacuum leak since the backfire condition existed with both carbs. Try partially covering the primary venturies to see if it's drawing air from another source. Hook up a vacuum guage and see what you've got.


Ron

Ron, just checked the plugs they do look a little on the rich side, as for vacuum leak I'll have to check, the carb has 4 corner idle so I think I will have to try to cover the hole carb and see if idle goes up. Or I'll have to use propane, not sure what the vacuum is I'll have to go and put my gauge on it and see and get back to you



                                                              Thanks, Alan

[69chargerR/T]

Alan, the timing looks fine....the initial and total are right where they should be with that combo. 

The motor is telling you it wants more fuel at the transisition. It's either the pump shot or a jetting issue. Have you tried jetting up on the primaries ? Have a look at the secondary accelerator pump adjustment as well. From your description it seems that once the engine is running on the main circuit (1500 rpm) there is no backfire which is good news. The problem lies in the transition from idle to WOT. Based on your latest report i don't think it's a vacuum leak....keep tuning bud ! 


Ron

Ron, checked vacuum at 800 RPM its at 15.5 in. in gear RPM is 650-670 it has 12.5-13.0 in. Checked for vac. leak put rag over carb idle didn't pick up. Plugs look a little on the rich side now with stock jet #71s front #80s rear. I do have a #37 pump nozzle and pump cams, I'll try the #37 nozzle first, as for pump cams thats the tricky part is choosing what cam to try !!! It has the pink cams on it, it seems that I need to make the pump arm move quicker,or sooner if you know what I mean. I'm not sure what cam to try do you have any idea what color cam I should try to do this Also what about tube type nozzles would they be better cause they shoot closer to the center of the throttle bore ??


                                                 Thanks, Alan




   PS: Do you think if I just go and get the voodoo 60303 cam and tune the carb to that cam will make this tuning job easer, and make the car quicker !!!!!!

[firefighter3931]

Alan, the timing looks fine....the initial and total are right where they should be with that combo. 

The motor is telling you it wants more fuel at the transisition. It's either the pump shot or a jetting issue. Have you tried jetting up on the primaries ? Have a look at the secondary accelerator pump adjustment as well. From your description it seems that once the engine is running on the main circuit (1500 rpm) there is no backfire which is good news. The problem lies in the transition from idle to WOT. Based on your latest report i don't think it's a vacuum leak....keep tuning bud ! 


Ron

Ron, checked vacuum at 800 RPM its at 15.5 in. in gear RPM is 650-670 it has 12.5-13.0 in. Checked for vac. leak put rag over carb idle didn't pick up. Plugs look a little on the rich side now with stock jet #71s front #80s rear. I do have a #37 pump nozzle and pump cams, I'll try the #37 nozzle first, as for pump cams thats the tricky part is choosing what cam to try !!! It has the pink cams on it, it seems that I need to make the pump arm move quicker,or sooner if you know what I mean. I'm not sure what cam to try do you have any idea what color cam I should try to do this Also what about tube type nozzles would they be better cause they shoot closer to the center of the throttle bore ??


                                                 Thanks, Alan




   PS: Do you think if I just go and get the voodoo 60303 cam and tune the carb to that cam will make this tuning job easer, and make the car quicker !!!!!!

Alan, i would bump the idle speed up to 800 rpm....no need to run it that low. I prefer the higher idle for several reasons but a big one is camshaft oiling. Remeber that the cam is splash lubed so increased idle speed helps to keep the cam/lifters well lubed. 

The idle vacuum sounds good....we can rule out a vacuum leak.

The squirters with nozzles are better....i like them. Also, when using a larger squirter you need to use a hollow screw....the std screw will not allow enough fuel to flow when the pump is activated. If you're not using the hollow screw with a bigger squirter it will not deliver the max volume that that squirter is designed for.

Generally speaking ; the standard pump cam is good unless there is a huge lean spot off idle. I will check the manual for some ideas.


Ron

[jg68]

Try putting in 73 jets in the primaries, the pink cam is on the lazy side, if you have an orange, throw that on, then start all over with a small squirter, i too like the tube type, if the plugs are dark, its most likely from alot of idling & its most likely on the rich side at idle, but when you cross over it goes lean while under load, i have a 3310 780 on my 446, it runs VG with 73/85 jets with a red cam & a 28 tube type squirter, also make sure the throttle blades are even F&R along with the idle mix screws, heres what my plugs look like now with the current set-up , NGK 5670-6s, So just keep jetting it up & calm down the squirter size, you'll be amazed

[69chargerR/T]

Alan, the timing looks fine....the initial and total are right where they should be with that combo. 

The motor is telling you it wants more fuel at the transisition. It's either the pump shot or a jetting issue. Have you tried jetting up on the primaries ? Have a look at the secondary accelerator pump adjustment as well. From your description it seems that once the engine is running on the main circuit (1500 rpm) there is no backfire which is good news. The problem lies in the transition from idle to WOT. Based on your latest report i don't think it's a vacuum leak....keep tuning bud ! 


Ron

Ron, checked vacuum at 800 RPM its at 15.5 in. in gear RPM is 650-670 it has 12.5-13.0 in. Checked for vac. leak put rag over carb idle didn't pick up. Plugs look a little on the rich side now with stock jet #71s front #80s rear. I do have a #37 pump nozzle and pump cams, I'll try the #37 nozzle first, as for pump cams thats the tricky part is choosing what cam to try !!! It has the pink cams on it, it seems that I need to make the pump arm move quicker,or sooner if you know what I mean. I'm not sure what cam to try do you have any idea what color cam I should try to do this Also what about tube type nozzles would they be better cause they shoot closer to the center of the throttle bore ??


                                                 Thanks, Alan




   PS: Do you think if I just go and get the voodoo 60303 cam and tune the carb to that cam will make this tuning job easer, and make the car quicker !!!!!!

Alan, i would bump the idle speed up to 800 rpm....no need to run it that low. I prefer the higher idle for several reasons but a big one is camshaft oiling. Remeber that the cam is splash lubed so increased idle speed helps to keep the cam/lifters well lubed. 

The idle vacuum sounds good....we can rule out a vacuum leak.

The squirters with nozzles are better....i like them. Also, when using a larger squirter you need to use a hollow screw....the std screw will not allow enough fuel to flow when the pump is activated. If you're not using the hollow screw with a bigger squirter it will not deliver the max volume that that squirter is designed for.

Generally speaking ; the standard pump cam is good unless there is a huge lean spot off idle. I will check the manual for some ideas.


Ron

Ron, idle speed is 800 RPM in park, in gear its 650-670 in order to get idle to 800 RPM in gear I would have to run idle speed at around 950 RPM in park, that I think is a little high. If I turn idle to 850 RPM in park idle will be around 700 RPM in gear thats about as high as I would like to go. Also I thought you could go as high as a # 37 squirter before you need a hollow screw I may be wrong, I have a #35 in there now.



                                 Thanks alot for all your help, Alan 

[firefighter3931]

Joe, those are some nice looking plugs. Good work dialing it in 


Alan, i looked in my Holley book and the pink cam should be ok for what you're doing. There are 3 different mounting holes to adjust the "shot" with the pink cam which is a #330 in case you were wondering. You might have to play around/experiment with the hole location on the cam to see if it improves.

One other thing that we haven't talked about is the power valve. The PV rating will have a huge impact on the transition....especially if it is sized incorrectly. Based on your vacuum readings i would be looking at an 8.5 PV if you don't have one in there allready.

For example ; assuming you have a 6.5 PV in there now and you're making 12.5in at idle then you're fuel enrichment circuit won't be activated until the engine vacuum drops down to 6.5. This creates a large hole in the transition with a resulting lean spot which will create the backfire. You may be getting adequate fuel volume to the engine but it might be coming too late. 



Ron

[firefighter3931]

Ron, idle speed is 800 RPM in park, in gear its 650-670 in order to get idle to 800 RPM in gear I would have to run idle speed at around 950 RPM in park, that I think is a little high. If I turn idle to 850 RPM in park idle will be around 700 RPM in gear thats about as high as I would like to go. Also I thought you could go as high as a # 37 squirter before you need a hollow screw I may be wrong, I have a #35 in there now.



                                 Thanks alot for all your help, Alan 

Alan, you are correct on the hollow screw....it's actually a 40 squirter and larger that needs them. You're fine with the solid screw and 35 squirter. 

Allthough the idle speed has no bearing on the current tuning issues i would still run it as high as you can tolerate for the aformentioned cam/lifter oiling.


Keep us posted on your progress....no doubt this will get sorted out and you'll be  with a big  on your face.



Ron

[69chargerR/T]

Try putting in 73 jets in the primaries, the pink cam is on the lazy side, if you have an orange, throw that on, then start all over with a small squirter, i too like the tube type, if the plugs are dark, its most likely from alot of idling & its most likely on the rich side at idle, but when you cross over it goes lean while under load, i have a 3310 780 on my 446, it runs VG with 73/85 jets with a red cam & a 28 tube type squirter, also make sure the throttle blades are even F&R along with the idle mix screws, heres what my plugs look like now with the current set-up , NGK 5670-6s, So just keep jetting it up & calm down the squirter size, you'll be amazed

jg68, I do have an orange pump cam I'll try that, and get some tube type pump nozzles. I don't know if I should jet up, car seems rich now with #71 primary jets plugs look dark and it even smells rich,but I don't know if its the mp cam that makes it smell rich the 770 avenger I took off had #72 primary jets and #75 secondary jets, when changed to the 750dp I put new pugs in, the ones I took out that were running with 770 looked rich to me ?? I'm running autolite 85s they are a little hard to read because the base of the plug is a dark color, I see a lot of guys on this site run NGKs,  Ron runs I think XR-5s. You run the NGK-6s, whats the difference I want to get a set of NGKs  and do a new plug check because I think I will be able to get a better plug reading before I do a jet change.


                                            Thanks for your help,Alan 

[jg68]

Allen, you will smell a richer idle with the MP cams, they have alot of overlap, but i still say you need to jet up, your dark plugs i'll bet are from a rich idle circuit, so you need to lean that area out & jet up the Main circuit, i'll gaurantee that stumble goes away, just try it & you'll see, but put back in a conservative squirter like a 31, it doesn't need to be the tube type at first, just try the 73s in the front & a 31 squirter with the orange cam in #1 hole.

Also, what are the idle mix screws at, how far out are they, & if you bring 1 in all the way, does it want to stall or come close to it, let me know

On the NGKs, they are very easy to read the "strap" area, the R5670 & 5671s are a Race style plug with a shorter strap (good for nitrous & rapid excelleration), the RX5s are a standard replacement plug but they do work very well also, i've gapped mine back at .035" & all is good, even with the Mallory Box. The Autolites are hard to read the strap, virtually impossible, Champs are easy to read also, but the NGK series are the Easiest

Hey Ron, those plugs do look good don't they , i found some Amoco 93 out on the interstate & also determined that i had too much total timing, its now at 35* & no more ping
Well the TR is long gone & i'm back to a single carb , i know, i know , but the TR was just too much WOT for my set-up, 1/2 throttle it was a monster, but who wants to run 1/2 throttle

So this is what i'm doing now, installing screw in bleeds & 4 corner idleing, this an 850 (4781) whatcha think

[69chargerR/T]

Joe, those are some nice looking plugs. Good work dialing it in 


Alan, i looked in my Holley book and the pink cam should be ok for what you're doing. There are 3 different mounting holes to adjust the "shot" with the pink cam which is a #330 in case you were wondering. You might have to play around/experiment with the hole location on the cam to see if it improves.

One other thing that we haven't talked about is the power valve. The PV rating will have a huge impact on the transition....especially if it is sized incorrectly. Based on your vacuum readings i would be looking at an 8.5 PV if you don't have one in there allready.

For example ; assuming you have a 6.5 PV in there now and you're making 12.5in at idle then you're fuel enrichment circuit won't be activated until the engine vacuum drops down to 6.5. This creates a large hole in the transition with a resulting lean spot which will create the backfire. You may be getting adequate fuel volume to the engine but it might be coming too late. 



Ron

Ron, carb does have a 6.5 power valve  in it, I wasn't sure if I should change the PV because at 850 RPM in park vac. is around 16in. but in gear RPM is 700 and vac. drops to around 12.5 to 13.0in. I'm going to try some more acc. pump adjustments if that doesn't work I'll try a PV change Ron, you didn't answer one question would it be better leave the car the way it is now ( its drivable ) and just get the voodoo 60303 cam ( I'm still saving for it) and tune the 750dp to that cam and be done with this problem   Don't mean to put you on the spot but, do think car will run better and not stink up my garage like the mp cam does, and be easier to tune!!!!!!!!!!!!

                                                                    thanks again,Alan 

 

[jg68]

Joe, those are some nice looking plugs. Good work dialing it in 


Alan, i looked in my Holley book and the pink cam should be ok for what you're doing. There are 3 different mounting holes to adjust the "shot" with the pink cam which is a #330 in case you were wondering. You might have to play around/experiment with the hole location on the cam to see if it improves.

One other thing that we haven't talked about is the power valve. The PV rating will have a huge impact on the transition....especially if it is sized incorrectly. Based on your vacuum readings i would be looking at an 8.5 PV if you don't have one in there allready.

For example ; assuming you have a 6.5 PV in there now and you're making 12.5in at idle then you're fuel enrichment circuit won't be activated until the engine vacuum drops down to 6.5. This creates a large hole in the transition with a resulting lean spot which will create the backfire. You may be getting adequate fuel volume to the engine but it might be coming too late. 



Ron

Ron, carb does have a 6.5 power valve  in it, I wasn't sure if I should change the PV because at 850 RPM in park vac. is around 16in. but in gear RPM is 700 and vac. drops to around 12.5 to 13.0in. I'm going to try some more acc. pump adjustments if that doesn't work I'll try a PV change Ron, you didn't answer one question would it be better leave the car the way it is now ( its drivable ) and just get the voodoo 60303 cam ( I'm still saving for it) and tune the 750dp to that cam and be done with this problem   Don't mean to put you on the spot but, do think car will run better and not stink up my garage like the mp cam does, and be easier to tune!!!!!!!!!!!!

                                                                    thanks again,Alan 

 

Allen not to answer for Ron, but that .484 is a very tuneable cam, i've run them before, your vacuum in gear is very good for that cam, most likely from the higher int. timing, i personally wouldn't change cams, those MP pieces do perform well, & you won't need to go through all the rigga-moragga BS with breaking in a new cam & crossing your fingers the cam don't loose a lobe , just keep playing with it, you'll get it dialed in, Ron & I will give ya all the help we can

[69chargerR/T]

Allen, you will smell a richer idle with the MP cams, they have alot of overlap, but i still say you need to jet up, your dark plugs i'll bet are from a rich idle circuit, so you need to lean that area out & jet up the Main circuit, i'll gaurantee that stumble goes away, just try it & you'll see, but put back in a conservative squirter like a 31, it doesn't need to be the tube type at first, just try the 73s in the front & a 31 squirter with the orange cam in #1 hole.

Also, what are the idle mix screws at, how far out are they, & if you bring 1 in all the way, does it want to stall or come close to it, let me know

On the NGKs, they are very easy to read the "strap" area, the R5670 & 5671s are a Race style plug with a shorter strap (good for nitrous & rapid excelleration), the RX5s are a standard replacement plug but they do work very well also, i've gapped mine back at .035" & all is good, even with the Mallory Box. The Autolites are hard to read the strap, virtually impossible, Champs are easy to read also, but the NGK series are the Easiest

Hey Ron, those plugs do look good don't they , i found some Amoco 93 out on the interstate & also determined that i had too much total timing, its now at 35* & no more ping
Well the TR is long gone & i'm back to a single carb , i know, i know , but the TR was just too much WOT for my set-up, 1/2 throttle it was a monster, but who wants to run 1/2 throttle

So this is what i'm doing now, installing screw in bleeds & 4 corner idleing, this an 850 (4781) whatcha think

jg68, The idle screws are are only one turn out, when I turn idle screw all the way in engine will not stall but it stumbles a lot. You helped me before with the 4 corner idle adjustment, I had to set the throttle plates, and I got the secondary throttle adjuster I have the throttle plate idle screws at one turn and engine idles at 850 RPM. Thanks for the info at this point I'll try any thing


                                                              Thanks, Alan

[firefighter3931]

So this is what i'm doing now, installing screw in bleeds & 4 corner idleing, this an 850 (4781) whatcha think

What do i think ? You're a madman....that's what i think !  You should be using that Thermoquad i sent you awhile back 

Looks good Joe....drilling and installing bleeds i see.    Making your own HP carb....trying to put Holley out of business. 

I must say you're determined....make sure and write up a manual so we can all learn from your trials and tribulations 

Are you gonna use a 750 baseplate or did you get one with the 850 dp'er. Looking forward to your results. 


Ron


Ps. Plugs look great....nice work !

[firefighter3931]

Ron, carb does have a 6.5 power valve  in it, I wasn't sure if I should change the PV because at 850 RPM in park vac. is around 16in. but in gear RPM is 700 and vac. drops to around 12.5 to 13.0in. I'm going to try some more acc. pump adjustments if that doesn't work I'll try a PV change Ron, you didn't answer one question would it be better leave the car the way it is now ( its drivable ) and just get the voodoo 60303 cam ( I'm still saving for it) and tune the 750dp to that cam and be done with this problem   Don't mean to put you on the spot but, do think car will run better and not stink up my garage like the mp cam does, and be easier to tune!!!!!!!!!!!!

                                                                    thanks again,Alan 

 

Allen not to answer for Ron, but that .484 is a very tuneable cam, i've run them before, your vacuum in gear is very good for that cam, most likely from the higher int. timing, i personally wouldn't change cams, those MP pieces do perform well, & you won't need to go through all the rigga-moragga BS with breaking in a new cam & crossing your fingers the cam don't loose a lobe , just keep playing with it, you'll get it dialed in, Ron & I will give ya all the help we can

Alan, the Voodoo grind would be much easier to work with, no doubt. Like Joe said the 484 cam is tunable and if you're happy with the engine's performance then you could stick with it for now. Personally, i don't like the long duration of that stick (238@.050) with a 108 lsa for a mild application because the idle is so "dirty". But that's not to say it can't work.

Knowing now that you have a 6.5 PV i can see a change in your future to something bigger. It would be a step in the right direction. I'm surprised that the 484 is making that much vacuum in gear. Did you advance the cam when it was degreed in ? You've got it tuned pretty good other than the off idle stumble, inmo.


Ron

[69chargerR/T]

Ron, carb does have a 6.5 power valve  in it, I wasn't sure if I should change the PV because at 850 RPM in park vac. is around 16in. but in gear RPM is 700 and vac. drops to around 12.5 to 13.0in. I'm going to try some more acc. pump adjustments if that doesn't work I'll try a PV change Ron, you didn't answer one question would it be better leave the car the way it is now ( its drivable ) and just get the voodoo 60303 cam ( I'm still saving for it) and tune the 750dp to that cam and be done with this problem   Don't mean to put you on the spot but, do think car will run better and not stink up my garage like the mp cam does, and be easier to tune!!!!!!!!!!!!

                                                                    thanks again,Alan 

 

Allen not to answer for Ron, but that .484 is a very tuneable cam, i've run them before, your vacuum in gear is very good for that cam, most likely from the higher int. timing, i personally wouldn't change cams, those MP pieces do perform well, & you won't need to go through all the rigga-moragga BS with breaking in a new cam & crossing your fingers the cam don't loose a lobe , just keep playing with it, you'll get it dialed in, Ron & I will give ya all the help we can

Alan, the Voodoo grind would be much easier to work with, no doubt. Like Joe said the 484 cam is tunable and if you're happy with the engine's performance then you could stick with it for now. Personally, i don't like the long duration of that stick (238@.050) with a 108 lsa for a mild application because the idle is so "dirty". But that's not to say it can't work.

Knowing now that you have a 6.5 PV i can see a change in your future to something bigger. It would be a step in the right direction. I'm surprised that the 484 is making that much vacuum in gear. Did you advance the cam when it was degreed in ? You've got it tuned pretty good other than the off idle stumble, inmo.


Ron

Ron, Right now I'm not happy with the cars performance since I put the 750dp on You and jg68 have giving me a lot of tuning suggestions I have not got them all done yet I'm going to get these tuning tips done this week and see if car performs better with this cam and carb When I did the engine over I just installed the cam strait up. I'm still saving up for that voodoo cam I might just make the change!! Going to make some tuning changes and see what happens, I think this engine combo has more power in it I'm just trying to find it,I don't know if its with the mp cam or with a different cam like the voodoo!!  I'll let you guys know how it goes And again I thank you and jg68 very, very  much for your time and help!!!!!!!!!!!!!!!

                                                                         thanks,Alan

         

                                                                   

[jg68]

Ron, still have the TQ, all i need is to get the throttle shafts redone & some new needle & seats, I just love working with Holleys , maybe i'm just crazy , but YES, i am determined, what i am starting is a little rebuild service on the side, & i'll convert anyones M.Bodies over with these mods, plus 4 corner idleing for around 70.00 finished in Bronze, i got some goodies from QF, billet m. blocks, aluminum bowls & 1.11/16 billet base, i picked up these 2 main bodies at a swap meet for a whopping 8.00 for both , i'm starting to collect an arsinal of parts too, i'm setting up the 800dp, i'll keep you up on progress

[SeattleCharger]

 

[firefighter3931]

Ron, still have the TQ, all i need is to get the throttle shafts redone & some new needle & seats, I just love working with Holleys , maybe i'm just crazy , but YES, i am determined, what i am starting is a little rebuild service on the side, & i'll convert anyones M.Bodies over with these mods, plus 4 corner idleing for around 70.00 finished in Bronze, i got some goodies from QF, billet m. blocks, aluminum bowls & 1.11/16 billet base, i picked up these 2 main bodies at a swap meet for a whopping 8.00 for both , i'm starting to collect an arsinal of parts too, i'm setting up the 800dp, i'll keep you up on progress

Joe, Is that the thermoquad i sent ya ?  If it is.....man it never looked so good. 

Great job on the carb restorations.    You're gonna put quickfuel and pro systems out of bussiness. 



Ron

[jg68]

Finished product, now to test it out