kcsoa22

Ok, I really just don't understand the relationship between CC's on head vs cam specs, with intake.

Basically I have a stock long block, stock cam, and an edlebrock performer intake. Thinking of going one of 2 routes. Ad the cam and alum heads or step up to a 347.

My question is the same either route, How do I decide if I want 165, or 185 cc heads? Does my cam also effect that decision? I was looking to keep the edlebrock intake either way, and was thinking of going with AFR heads, and cam. Obv iously the bigger the ports the more air it flows, but how do I decide which is right for me, or which is too much?\

Any help is appreciated, I know there are lots of H/C/I threads but I could not find one discussing how to choose a size.

Thanks in advance!

aode08

at least you used search, Ill let others chime in, but dont cheat yourself out of those extra cubes

Hell, im thinking of removing my passenger seat to reduce weight, is that a good ideah?

mjr46

It's a start, they say for every 100 lbs removed you can expect to see a tenth of a second increase in the 1/4 mile

aode08

well no one wants to sit in it



back to the original issue,

CC = Combustion Chamber

Camshaft= Valve lift and Duration Operator.

64cc chambers , good for boost(supercharger).

59c (Higher Compression,Good for Naturally Aspirated Engines)

You Can have 64cc heads, milled to 59 cc for higher compression.


A 347 with some AFR 185 Heads, and a Custom Camshaft and Tune will be sick.

A 302 with AFR 165's , and Intake Manifold Typical 280rwhp , 3O0rwhp with a tune and supporting mods..

67mustang302

Cam size and head size are going to be determined by engine rpm and displacement. A larger size engine needs a bigger head and cam and a smaller engine obviously a smaller head and cam. Higher rpm wants more head and cam, and so on and so forth. A moderate rpm 302 is better off with 165 and a cam matched to the same rpm range, and higher revving 302 will want the bigger head and cam. Something like a 347 would want the bigger head and cam just to run in a normal rpm range, the smaller head would just choke it. A bigger head CAN flow more air, but that does not mean that it WILL flow more air. Too big a head on an enginewill reduce the induction velocity, which in turn will reduce power output, which in turn will reduce the pumping effectiveness of the engine, which means that the flow potential of the head doesn't get used, and it wasted. Also an engine that has a choke point somewhere else will never move the potential airflow through the head, since there's a restriction elsewhere in the system.185's on a stock cammed, stock intake etc engine would basically be a waste, it'll make more power than stock, but will make less average power than 165's would, but with a higher peak number(which only looks good on paper). Basically you need to select a head/cam/intake setup that's matched to where you drive the engine in it's intended use, ie street cars run anywhere from idle up to around 6,500rpm, or a race car that operates from 5,000-8,000rpm. Generally speaking though, most street 302's are better off with 165's, and most 347's are better off with 185's, but that's a pretty broad generalization, and it all really comes down to build. Someone who knows what they're doing could easily build a 185 headed 302 that craps burning coals and has plenty of part throttle power and drivability.

FWIW I'm running AFR 165's on a 302, and making around 310-315 at the wheels with a 570cfm carburetor(that was before spacer tuning), and I don't turn more than 6,000rpm(granted though, it's not the typical 302). It drives really well, and is reliable. If I had a lower gear I prolly woulda gone with 185's and a slightly larger cam

w8less

fixed it for you