Hi guys i was wondering if you gus could help me figure out what kind of cam i need to put in my 347 i am building i just bought a set of afr 185 heads now i need to try to macth cam and intake up with them i am running a carb is a 750 hp seris holley please let me know what you guys think thank you
what kind of cam and what size
- Thread starter one_bad_91stang
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88Stangboy
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First off a 750 carb seems a little big for a mild street 347, more like a 600-650 would be plenty for mild street engine. Of coarse im just assuming its a mild street engine. Really need more info on the use of the engine. Is it a strictly street engine, daily driver..etc. But engines really dont need as much carburetion as you would think. You want to look at the cubic inches and the best volumetric efficientcy. If the cylinder completly fills with air/fuel at regular atmosperic pressure than it is said to have 100% volumetric efficienty. With street engines VE is typically around 75-80% Boost the perfomance and it goes up to about 80-95%. Put a supercharger or turbo on the engine and it go's above 100% because the engine is not longer sucking it's own air, its being pushed into the engine (boost) If the engine is N/A then the VE is going to be below %100 If it has supercharger than its going to be above %100. THe easiest way to measure it besides a dyno is to use the software Engine Analizer or Egnine analyzer pro. The best way to calculate the CFM on a carb is to.
VE X cubic inches X Max Rpm's Divided by 3456.
So if you had a 347 that had a max rpm of 6500 with a volumetric efficientcy of 85%(estimate) Do the match and then you would need a 600CFM carb. I would go with a 650 just so i could grow into it.
Intake, headers, cam, etc. decide your VE. But typically for a street driven N/A 347 its usually in the neigborhood of about 80-85%(estimating here from what ive seen)
That probabablly didn't help you worth a damn with your cam, but im in a good mood and felt like explaining something, but to big of a carb is just a headache...just thought i would help you on that...sorry
VE X cubic inches X Max Rpm's Divided by 3456.
So if you had a 347 that had a max rpm of 6500 with a volumetric efficientcy of 85%(estimate) Do the match and then you would need a 600CFM carb. I would go with a 650 just so i could grow into it.
Intake, headers, cam, etc. decide your VE. But typically for a street driven N/A 347 its usually in the neigborhood of about 80-85%(estimating here from what ive seen)
That probabablly didn't help you worth a damn with your cam, but im in a good mood and felt like explaining something, but to big of a carb is just a headache...just thought i would help you on that...sorry
88Stangboy
Banned
86bluecobra said:
I agree, i mean you can pick one off the shelf and try to match it with what you have, or you can build the engine around the one you picked off the shelf. Custom cams are the way to go. Its designed to make the absoblute most of YOUR combo, not the 34,495,593,580 other people who buy the same cam.
