poor low end???

[metcoll]

i have a 70 charger with 030 over 440 six pack pistons, lunati 240/250 @ 050 w/520/547 lift cam,452 heads with a valve job torker 2 intake & 750 double pump carb with machined air horn,13/4 hedmann headers...4.56 gear & 3000 stall converter...it seems the car has decent throttle response but right out of the hole it doesn't seem to have a lot of tire smoking torque....a friend of mine had the same cam in his 383 & it would just smoke the tires at any speed.....would going to an performer rpm manifold make any noticeable difference ...thx for any input.....

[superduperbee]

I don't think your intake is the problem. You didn't mention what type of ignition system you have, so I would start there. If you don't have it already, I would recommend the Mopar Chrome box or aftermarket equivelant. Also lightweight distributor springs to speed up the timing curve. You have a fairly balanced combination, you need to have the right timing curve. If ignition is ok, I would start experimenting with carb jetting, check accelerator pumps. Also make sure cam is degreed in properly, you'd be surprised how many timing sets are a little off.

[RD]

two things, your intake (single plane) not good for torque production at the low end, and your stall is too small.  that sort of build requires a 3800 stall minimum to get you in the range where torque is plentiful using a single plane intake and the duration at which your cam is ground for.

also, a suggestion would be to get a different carburetor... Get a speed demon 850 or a holley 850 to get the most out of that engine.. with more cubes comes the need for more fuel and air.

lastly, with those gears, obviously this car is not a highway cruiser right?  so why did you go so low on the stall with that combo?  I would jettison the torker, put on an M1 or holley street dominator single plane, put on a speed demon, and get a bigger stall. you will be surprised of the results.  I know it means more money, but it would really wake up that engine.

are you a bracket racer or a street driver.  answer that question and it may give different results.

[firefighter3931]

i have a 70 charger with 030 over 440 six pack pistons, lunati 240/250 @ 050 w/520/547 lift cam,452 heads with a valve job torker 2 intake & 750 double pump carb with machined air horn,13/4 hedmann headers...4.56 gear & 3000 stall converter...it seems the car has decent throttle response but right out of the hole it doesn't seem to have a lot of tire smoking torque....a friend of mine had the same cam in his 383 & it would just smoke the tires at any speed.....would going to an performer rpm manifold make any noticeable difference ...thx for any input.....

Was the cam degreed in ? Where is the timing set ? The stall is a little on the smallish side for that combo, inmo 


(1) make sure it has enough advvance at idle. You should have 18* at idle and 36-38* all in by 2500 rpm for best performance.
(2) the Intake is not ideal but should work OK in that application with the deep gears
(3) The 750 dp'er is OK as well...an 850 might make a few more HP on that build but it will lose some low speed manners and throttle response.


I would concentrate on the timing curve first and once that's dialed in look at tuning the carb.....tuning, tuning and more tuning 




Ron

[metcoll]

sorry forgot to mention i have a msd billet distributor & 6A box........

[Rob R]

a 440 with 4.56 gears and a 750...hum...not to go against the resident expert here but I believe the carb is too small...just try a 37 or 41 shooter and see what happens...make sure you haven't glazed over the plugs...I'll bet that the porcelain is yellow at the tip...start with fresh plugs any time your trying to sort out a carb problem...just my take on it

[firefighter3931]

sorry forgot to mention i have a msd billet distributor & 6A box........

In that case throw the black bushing in it and set the base timing to 18* at idle and see how it responds. 

a 440 with 4.56 gears and a 750...hum...not to go against the resident expert here but I believe the carb is too small...just try a 37 or 41 shooter and see what happens...make sure you haven't glazed over the plugs...I'll bet that the porcelain is yellow at the tip...start with fresh plugs any time your trying to sort out a carb problem...just my take on it

It might be slightly small for a max effort build but going to an 850 wouldn't make that much of a difference....in my opinion. 

Basicly stock heads with an open plenum intake manifold won't use anywhere near 750 cfm at WOT. My buddy runs a very similar combo with the 509 cam, 3800 lbs, 4.10's and 3500 stall ; 11.80's at the track with a 750 dp'er.

It might want more fuel (jetting) but it won't need more air (CFM)....like Rob said, check the plugs and jet up as required. 



Ron

[Rob R]

I figured after tuning these things for 30 years I should have picked up something by now...I guess not  ...a 440 with a 250@50 cam and a 4.56 gear is falling on it's face...hum...

[firefighter3931]

a 440 with a 250@50 cam and a 4.56 gear is falling on it's face...hum...

Tell that to Runner (Mike) who runs the 750hp dp'er on his 71 Roadrunner with a lowdeck stroker and stock E-heads with a 244/250 Comp XS solid/3800 stall and 4.57 gears. 11.35@119 mph is hardly falling on it's face.   

Mike had a thread going awhile back on Moparts and was considering a Biggs 950 hp and Jesse from Biggs responded on that thread....and basicly told him that it wouldn't be worthwhile upgrading to the 950 given the current performance of his engine.  That was a good answer from an honest vendor....Jesse is all right in my books. 

I figured after tuning these things for 30 years I should have picked up something by now...I guess not  

Rob, i highly doubt that is the case. 

But....there's more than one way to skin a cat. 



Ron

[Rob R]

Yep...
lot's of ways to skin an old 440

Just like that Cuda I did...446...ported 906's...Engle K62 with a solid lifter on it (made 10 more hp) ported M1 and a 1050 with 3.55's it went 11.50 at 119

[firefighter3931]

Yep...
lot's of ways to skin an old 440

Just like that Cuda I did...446...ported 906's...Engle K62 with a solid lifter on it (made 10 more hp) ported M1 and a 1050 with 3.55's it went 11.50 at 119

Now that's a nice running combo ! 

What kind of lash were you using with that cam....interesting. 


Ron

[Rob R]

I ran .006 on both in and ex because that's all the ramp that's ground into it...not a cam for beginers...makes ferocious power and sets the valve down HARD...way too fast a cam for a hyd lifter even at .000 lash...it would be a good idea to get Mark to grind a solid lifter quieting ramp on this grind.

[firefighter3931]

I ran .006 on both in and ex because that's all the ramp that's ground into it...not a cam for beginers...makes ferocious power and sets the valve down HARD...way too fast a cam for a hyd lifter even at .000 lash...it would be a good idea to get Mark to grind a solid lifter quieting ramp on this grind.

Thanks for the info Rob. 

Have you looked at the Engle KV solid profiles....they look pretty agressive too. 


Ron