Pistons bottom out

[Dhadley]

Re: Pistons bottom out

Your powerhead is from 1973. You'll have to use only 1973 pistons, rods and rod bearings. The 1973 crank is the only one that fits a 1973 block.

 

[Josedcr]

Re: Pistons bottom out

Your powerhead is from 1973. You'll have to use only 1973 pistons, rods and rod bearings. The 1973 crank is the only one that fits a 1973 block.

I'm guessing that someone put the wrong freeze plug on the block. Do you think is better to get a 1978 140 block and crank shaft since I already have the rods and pistons and heads for it. Wold I have to have carb and ignition systems for 1978 or can I use what was installed on the 1973? Would the 1978 block even fit the lower unit? Any advise will help... Thaks

 

[emdsapmgr]

Re: Pistons bottom out

The powerheads are not interchangeable. When OMC went from one thermostat to two, they changed the midsection adapters and the design of the bottom of the powerhead.

 

[Dhadley]

Re: Pistons bottom out

The 1973 block has the same mounting bolt pattern as blocks from 1974 to (basically) 1976 and some 1977 V4s. The 1972 is different.

Whatever direction you decide to go you'll need to keep the block, crank, rods, rod bearings and pistons the same year (either all 1973 or 1974 to 76).