Quote:
Originally Posted by Steve C.
"Any back to back comparisons like Jim made going from iron to aluminum and back to iron?"
For interest here does anyone have the results with Jim Hands testing doing the swap and numbers involved. What aluminum head was involved..
TKS.
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Going from memory the car was running 11:50ish and it lost about a tenth with the aluminum heads. I think there was a slight mph gain with the aftermarket heads. It was a KRE aluminum d-port and a 250+cfm iron head
Its an excellent example of comparing "port volumes". The larger port volume heads made more power but couldn't run as quick.
Exactly why a well tuned 71 Trans Am will run away from a 336 geared LS-6 Chevelle.
Also a great example why "port volume" matters