Carb/Intake combo question

[69chargerboy]

I'm going to buy a Proform #67205 750 CFM Race Series Vacuum Secondary Carburetor and mate it with an Edelbrock RPM intake, the 440 has stock heads that were ported. Will I be "choking"  the exhaust flow if I were to install HP manifolds instead of a quality set of headers? I think I answered my own question, but I wanted some experienced advice. Thanks! 

[Ghoste]

A little but the FAST series require manifolds and they seem to do okay. 
No question that tubular headers would be better but if its manifolds you want it isn't like you are completely throwing your top end money away either.

[69chargerboy]

That's cool, You think it's too much carb or the wrong type of carb for my application?

[Ghoste]

No, I don't know the rest of your combination but I can't see it being a bad choice unless you're putting it on something with low compression and some sort of "mileage minder" camshaft.

[69chargerboy]

I'll have to dig up my engine builders spec sheet on my engine, I don't know the specifics off hand. All I could remember is it was bored .040 over, ported stock heads, Mild cam, KB pistons... I know he told me he lowered the compression so it could run on premium pump gas, if that makes sense......

[Ghoste]

It does and it wouldn't hurt to check but when I said low, I meant blower piston like 7.5:1 or something.  I'm going to guess your builder is giving you 9.5 or 10 to 1 and that the cam has been picked accordingly.  Mild porting and the Performer RPM are fine and Ron has been one of the busiest endorsers out there for Pro Form carbs.  I have no experience with them but Ron liking them says volumes.

[firefighter3931]

That is a very good induction package for a mild 440.....how well it runs with HP exhaust manifolds depends on the cam profile. Cams with shorter overlap and longer exhaust duration respond well with restrictive exhaust systems. 

What are the cam specs ?


Ron

[69chargerboy]

That is a very good induction package for a mild 440.....how well it runs with HP exhaust manifolds depends on the cam profile. Cams with shorter overlap and longer exhaust duration respond well with restrictive exhaust systems. 

What are the cam specs ?


Ron

Thanks for chiming in Ron, I'll have to wait till I'm home to see the invoice from my engine builder. All I remember that its a Comp Cams part, I'll get the part numbers a little later... Thanks!

[firefighter3931]

All I remember that its a Comp Cams part, I'll get the part numbers a little later... Thanks!

Most of the off the shelf Comp grinds are 110* lsa and many have a split pattern which should work descent with the manifolds as long as the duration is reasonable. When you post the cam specs or grind # try and list other specifics as well ; stall speed (if auto) and rear end gearing + tire diameter. 



Ron

[69chargerboy]

Ok  Ron, heres what I have...

Comp Cam 21-237-4 Magnum, 280H Serious Street/Strip, for 9:1 to 10:1 Compression   Link:  http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=701&sb=2
231* @ .050 Duration
280* Advertised
480 Lift
110* Lobe centers

KB 184 pistons
822-16 Com cam lifters - High Energy Lifters Link: http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=822-16&Category_Code=

3000 Stall Converter
The rear end is my stock R/T's  3.23

Thanks for all your help!

[firefighter3931]

The 280H is a nice single pattern cam ; not too agressive and easy on parts. Good thing you have a 3k stall because that 230@.050 profile starts to come on at 2600-2800 rpm so it will want a looser than stock Tq converter. 


It (280H) should work fine with your existing combo and manifolds but i would highly recommend a good quality 2.5in mandrel bent exhaust system with an X-pipe built in. The X-pipe really helps with cylinder scavenging....especially important with restrictive manifolds. All the FAST racers run x-pipes and they work great. Avoid flowmaster mufflers or any chambered muffler for that matter...too restrictive and they will rob power. Use either a Magnaflow or Ultraflow muffler.....the Magnaflows are quiter than the Ultraflows but neither are anywhere near as loud as the FlowBastards. 


The 3.23's will work OK but a deeper gear would be preferable, especially if you are planning on running a taller tire like the 275/50/15's. 


Keep us up to speed on your progress....when you get it up and running we can work on tuning the ignition and fuel curves for maximum performance. 



Ron

[69chargerboy]

The 280H is a nice single pattern cam ; not too agressive and easy on parts. Good thing you have a 3k stall because that 230@.050 profile starts to come on at 2600-2800 rpm so it will want a looser than stock Tq converter. 


It (280H) should work fine with your existing combo and manifolds but i would highly recommend a good quality 2.5in mandrel bent exhaust system with an X-pipe built in. The X-pipe really helps with cylinder scavenging....especially important with restrictive manifolds. All the FAST racers run x-pipes and they work great. Avoid flowmaster mufflers or any chambered muffler for that matter...too restrictive and they will rob power. Use either a Magnaflow or Ultraflow muffler.....the Magnaflows are quiter than the Ultraflows but neither are anywhere near as loud as the FlowBastards. 


The 3.23's will work OK but a deeper gear would be preferable, especially if you are planning on running a taller tire like the 275/50/15's. 


Keep us up to speed on your progress....when you get it up and running we can work on tuning the ignition and fuel curves for maximum performance. 



Ron

Thanks Ron, sounds great. I may run a 15" tire, but I am toying with the idea of a 18" tire like Keepats 68 Charger or autodynamics 69.  If you could, what would be a fair ballpark figure of horse power if I went with this current configuation added a good set of headers and X pipe exhaust system from TTI? Would that be more of an ideal set up if I wanted to get all the horsepower from this combo? Thanks, John

[firefighter3931]

Thanks Ron, sounds great. I may run a 15" tire, but I am toying with the idea of a 18" tire like Keepats 68 Charger or autodynamics 69.  If you could, what would be a fair ballpark figure of horse power if I went with this current configuation added a good set of headers and X pipe exhaust system from TTI? Would that be more of an ideal set up if I wanted to get all the horsepower from this combo? Thanks, John

The TTI 1 7/8 x 3 headers would be ideal for that setup. Adding the headers will be worth an easy 30-40 hp and better top end power. If the heads flow well then it should make in the 420-435hp range with close to 500 ftlbs of tire twisting torque. Headers allways make more power (HP & TQ)....that is an indisputable fact. 

Depending on the tire diameter you may want to consider a deeper gear out back. 


Ron

[69chargerboy]

Thanks Again for the advise... With this combo, how much more horsepower would a good set of aluminum heads make, like Indy, Edelbrock, etc...? Happy New Year!

[firefighter3931]

Thanks Again for the advise... With this combo, how much more horsepower would a good set of aluminum heads make, like Indy, Edelbrock, etc...? Happy New Year!

Again, it boils down to how well the original head flow but typical gains are 50hp with a set of E-head rpm castings. If you think that you might go in that direction in the future then purchase the TTI headers now....they fit fantastic with the angled plug RPM castings.

To get the most out of a set of aluminum heads you will want to upgrade the cam and possibly the valvetrain to access the increased high lift flow. 


Check out Vegas Mike's 440 in the proven combo's section....pretty basic build but some well matched components and lots of power on pump gas. 



Ron

[69chargerboy]

Awesome Ron, Your the man!

[john108]

[RON]
Excuse Me, But Just a Little Curious With the Following Statement:
"To get the most out of a set of aluminum heads you will want to upgrade the cam and possibly the valvetrain to access the increased high lift flow"
With the E-Heads, What upgrade is required to the ValveTrain?

[flyinlow]

E heads work with the stock valve train with mild cams. ( hydraulic ) I have a Lunati cam .494/.513 lift. Mopar HD. steel rockers . Stock pushrods.

Check that lifters are not bottom or topped out. If your block has been decked or heads milled you might need adjustable valve train.

high lift or solid lifter cam would be a different story.