Choosing a Manifold:SBF

[SSDiv6]

Originally Posted by FireSail

68 Cougar 302/230 stock heads
Intake: 1783
Exhaust: 1457
Head cc: 49.5
Rocker Ratio: 1.6

AFR 1399
Intake: 1900
Exhaust: 1600
Head cc: 58
Rocker Ratio: 1.6

Edelbrock 60217 heads (stamped NHRA Accepted)
Intake: 1900
Exhaust: 1600
Head cc: 60
Rocker Ratio: 1.6

If valves have to match stock +.005 like the rule book states, then neither of these heads listed as SS replacement heads in the Stock Car Classification Guide can be used without basically remanufacturing them down to factory specs. Why would NHRA approve heads that come either supplied or ready for valves that are too big?

Some posters on this forum make building for stock or super stock way too complicated. I refuse to be deterred.

Dale

You are correct and like I said before, there are no off-the-shelf bolt on parts for the class.

They approved the specific replacement heads because the rules allows you to replace the valve seats in both Stock and Super Stock classes. The rules are very clear that the cylinder heads must maintain stock head and stem size. The spec applies to the combustion chamber size too.

It's not complicated as long as you follow the rules and not subject to interpretation.