Anybody know anything about the ZP blocks that came in the jeeps? My 69 has a ZP block that I have to believe was stock (might be wrong but I really don't think so, wouldn't be the first time tho'..) but the casting number of 1241748 shows it as a 72 (atlantabuick.com) or a 75-78 X motor (cehighperformance.com) or a 71-80 H/J motor (butlers-a1.com). buick Also wondering about the internal differences between the PP/RP/SP engines and their low output counterparts. I know that the combustion chambers in the heads were different in various years (58?,53,50cc) but what about flow characteristics, and cam and crank differences? Can anybody shed any light or casting numbers? Mike
The blocks and cranks are virtually all the same. Starting in 73, they switched to the 'capscrew' rods - which are the preferred rod to use!:TU: The obvious differences are the compression, cams and heads. The 70 GS 350 was the pinnacle of Buick 350 performance. It had 10.25 rated compression, better cam and lower combustion chamber cc's. Around 73, they changed the heads to bigger size exhaust valves. Any of the heads can be made to flow pretty well, though. First choice would be the earlier heads - smaller chamber cc.
