Food for Thought

[DanEC]

Originally Posted by DanEC

A 428 CJ is not very different from a Q-code 427/400 HP center oiler from the 63 - 64 era other than a bit less bore and bit more stroke .

I guess I should have said also a bit less cam and compression. And I think KC's assembly care was probably a bit greater than standard FOMOCO at the time.

Originally Posted by marcocsx3121

Closer to the answer i was seeking. The resurgence of the 427 vs. 428 debate really inspired my original post. Given the differences between the two, I suspect that those 390 manifolds hurt the shorter stroke/higher revving 427 more.

I would say so too. Using Chevy for a comparison may not be popular but the 427/390 L36 hydraulic motor was rated at 390 HP in the Corvette with streamlined manifolds but lost only 5 Hp when put in an Impala with log type 396 manifolds and Chevy very clearly said it was due to the exhaust. The higher revving 1965 396/425 Corvette with streamlined exhaust manifolds dropped to 396/375 when it was put in the Chevelle that year with a bit milder hydraulic cam (vs mech in Corvette) and standard 396 manifolds to fit the chassis. Even later year 396/375 motors with the L72 mechanical cam kept the 375 rating with the log manifolds in the 66 and later Chevelles, Camaros and Novas.