" From: farna@xxxxxxx " " Early sixes had big ports, but had a tight 90* turn and don't flow as " much as 4.0L heads on the intake side. Exhaust ports are pretty big " too. At best you'd need to match ports and ramp the manifolds to " prevent turbulence in the exhaust port to manifold intersection. i guess if i was gonna get serious about this, i'd hunt up a late ['72-4] shaft rocker head or just swap over to a bridged-rocker one. both have smaller ports than the '60s head that flow better; iirc the main change is the port floors. all heads '68-'76 have 66cc chambers; '64-7 are 56cc, '77-'80 are 74cc. team it with an '80s water heated intake and mopar holley 2280 [bbd replacement]... ________________________________________________________________________ Andrew Hay the genius nature internet rambler is to see what all have seen adh@xxxxxxxxxxxxxxxxx and think what none thought