small block Ford

[václav]

Hi,
can I ask you:
I have Cobra, engine 302, block Roller, new pistons - Keith black ( flat )
Heads - Edelbrock performer RPM valve 2.02 1.9 Roller Rockers 1.6 Crane Cams
Intake manifold weiand stealth carburetor Holley double pumper 750 cfm
Camshaft Comp cam Magnum 280/280.


And just now.
What do you think about this configuration?
Is this good choice?

Thank you verry much for your answer.
Vaclav
Czech Republic

[David Hodgson]

No one got a comment for this guy? I reckon any Ford donk in a Cobra is a good choice.

As for the intent of your question, there are so many combinations you could use, but I think what you've got there will certainly leave any Skoda eatin' dust.

[jarendall]

I am running about the same setup, I had a 750 Eldelbrock, thought it was too much carb, so I changed to a 670 Holley, with the Edelbrock the engine dynoed at 348 HP, don't know about with the Holley, have run it up to 130mph, at that speed the car starts floating, so I backed off, don't know what the top speed would be, the setup you have will be very powerful and all you will need

[*13*]

Sounds like a nice setup! I would probably start with a 650 carb unless you are really going to spin some high rpms. The smaller carburetor will give you better low rpm response & power.


I will be visiting Prague in October. I hear it's a beautiful place! Can't wait

[Tommy]

Here's this amatuer's opinion on chosing parts for an engine. The heads will ultimately determine the air flow in and out. The valve train will determine the upper RPM limit, and the crank and pistons will determine upper limit on compression ratio. Varying any component may affect others. For example, flat pistons may produce 8:1 compression with one set of heads and 10:1 compression with another. .... It's difficult to express an opinion on the components you listed because they can be used to assemble a moderately strong, meduim compression long lasting engine, or a high compression monster that will require racing fuel and be on the verge of self destruction. It's all in how the parts are put together. Good luck with your engine.

[Cobra 29]

On my FMS 351W crate engine I run a 650 4150 DP on the Stealth manifold and the two work very well together.

[427SnakeSC]

I am running pretty much the same on my 302, Aluminum heads and intake, 750 Holley, Hydralic roller cam, Accel ignition. My compression ratio is 10:1. I don't have any complaints. The carb has vacuum secondaries and I don't feel it is too much for the motor.

[Dwight]

If you use the auto math formula, it says you need a 541 cfm carb for a 302 motor at 6500 rpms.
Dwight

[David Hodgson]

The formula Dwight used is probably this; CFM = (Cubic Inches x RPM) divided by 3456) x Volumetric Efficiency

example 1; standard 302 with factory exhaust/intake etc revving to 5000rpm would have a VE of about 80%. In the formula (302 x 5000)/3456 x 80% = 349.5 cfm, hence the 2 barrel Carter carby used for non performance cars.

Example 2; a strong 302 with aftermarket headers/intake, better camshaft, some head porting, etc revving at 6500 would have a VE up around 95%. Thus, (302 x 6500)/3456 x 95% = 540 cfm. Therefore a 600cfm would work fine, in fact I am using a 600 DP Holley, quite happily.

A bigger cam and major port work, tunnel ram and 7500 could see about 110% VE and would obviously flow more CFM.

The CFM figure is how much the engine is drawing in, so for best results not to cause a restriction, go at least one carby size up. Checked on a dyno, you would also find that several sizes up could help top end power but you would see a drop in bottom end torque, how noticable these gains/loses are under foot, would depend on factors like gearing and weight of vehicle.