Posted by Fred (208.220.185.2) on May 03, 2001 at 17:46:35:
In Reply to: nearly nothing will swap posted by 74merc on May 02, 2001 at 20:09:37:
I haven't done the swap, but I have been freshening up my 302. To say the 70's blocks suck is . . .lets just say the only real difference is two small threaded bosses in the oil valley , used to attach the roller lifters retainer (Spider). If you are planning on doing some serious over boring and stroking the pre 75 blocks actually have thicker webbing to hold the bottom end together. Also there are several after market conversions to get Roller lifters if that is what you want. The heads are also a little different, but they all inter change. The more popular stud type was introduced in the 80's, but again the 70's can be tapped to accept the threaded studs. Remember 75 they started using air injection for emissions, keep this in mind if you have a 74 or earlier Mav.
As a personal note 351 Windsor heads use slightly larger valves (1.84 intake, vs. 1.78. I forget the exhaust) than the standard 5.0/302/289.
Exhaust has proven a challenge, Not much room between the heads and shock tower. and the fuel tank is off center.
Good luck