Originally Posted by cowboy.2010
Hey guys, my brother and I are building a couple pure stock circle track cars and are trying to find out which engines have the most potential. He is building a 1978 firebird with chevy engine and I am building a 1965 ford galaxie. The rules are, must be small blocks, MUST BE OF SAME MANUFACTURE AS CAR, NO AFTERMARKET HEADS, INTAKES NO HEADERS, MAY HAVE DUAL EXHAUST, AND ENGINE MUST MAINTAIN 15" OF VACUUM AT 1000 RPM. I was just wondering what you guys reccommend. I was thinking of going with 351 windsor or possibly 300 straight six since i'm a 300 six freak lol. My brother is thinking of going with a 350 or 400 chevy. I no theres pros and cons about every engine but, was just wanting to here your opinions. Thanks
No to the 300, the rules unless they are a lot different for an inline 6 are just to restrictive, not only are you giving up 50 inches against 350's or 351's in the Ford case, but the manifold rules will kill you on getting more carburation which the 300 really needs. Associated with the manifold issue is the hard to get around fact that inline 6's with what essentially is a log manifold has very large mixture distribution issues compared to the typical V8 with a much more compact layout that is designed to minimize cylinders from stealing mixture from each other. As poor as V8 intakes tend to be, they are much better than inline intakes at fairly dividing the mixture up per cylinder.
A 351 with Chevy valves is one effective way to go if the rules will allow it. Chevy rockers on 7/16ths studs, if you can, with guide plates if possible. I you must use a self aligning rocker Chevy rockers are way ahead in weight reduction than the Ford rail rocker on the stem end which is favors a few more revs by unloading some of the mass times lever arm length the valve spring has to deal with. Another way to go with the 351 is 302 GT40P heads if the rules will allow them, still Ford to Ford, with Chevy valves and rockers as the GT40P's are designed for the smaller 302 and now need to feed the larger 351. This gives better porting and a way better combustion chamber that the typical 351 head, to come close to this with a regular production head you'd need to score a pair of 69-70 heads which is mighty hard to do.