block swap

[splitshot]

will a 1975 85 hp block swap out for a 1981 115 ?? found a good block my old one is junk looked up the p/n for the crank and main bearing they list different numbers so i wasnt sure if it would work or not...thanks for any help

 

[tashasdaddy]

Re: block swap

the 75 is a hydro mechanical shift motor, the 81 is a mechanical shift motor, the splines are different among other things. for your 1975, you need a 73-76 block. check here http://www.boatmotors.com/motorparts/

 

[splitshot]

Re: block swap

i have all the internals for the 1981 115 i need a block to put them in.. what year block will these guts fit in ?? i was hoping the 1975 85 block would work for my internals...

 

[Dhadley]

Re: block swap

Actually the crankshaft splines are the same. The 1975 block & crank has a smaller center main bearing. The mounting bolt pattern is different too.

What you'll be looking for is a 1979 & newer V4 crossflow block (don't worry about hp). The blocks with larger center mains (to match your crank) are easy to identify. The lower pan mounts on the front half of the block are cast as part of the front half. Blocks with small center mains have lower pan mounts that are bolted on.

If you can't find one, shoot me a PM.

 

[Faztbullet]

Re: block swap

Sorry Splitshot but no go, the 85 uses smaller pistons,different crank,smaller mains bearings,different porting,bolting pattern. You will need a 1978-1991 block for your parts to fit. What is wrong with your block to make you thing its junk?

 

[splitshot]

Re: block swap

well its busted at the base if you were looking at it from the back its under the exhaust plate around where one of the studs are in the back there is about a 3" piece missing..thanks for the info i really appreciate it