1972 omc 155 225 Buick cracked block

Ademuth

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Oct 7, 2015
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I have a 1972 omc electric shift 155 with a cracked block. I know I can swap a 225, however are there any other options? I can get a donor boat for $300 with a running ford 302 and 190 electric shift stern drive but I don't think the motor mounts will line up. Transom hole seems the same. Are mounts easy to move? Is this an option? Like the boat and everything else is in great shape, but 225s are hard to find. Plus I would like the extra horsepower. Boat is a 17 foot Peterborough.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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weldome aboard.

the ford has a different bolt patern than the old buick so you will need a complete carb thru intermediate housing anyway. However you are correct, the mounts will be in a different location. transom cutout should be the same.

mounts are just fiberglass and wood.

If it was me, and I had to attack a hull with fiberglass, I probably would replace the transom, seal up the giant OMC hole, and look for a 4.3 liter with a mercruiser or volvo outdrive and ditch the OMC stringer drive all together. Swapping one obsolete motor and obsolete drive for another slightly less obsolete motor and equally obsolete drive doesnt make much sense to me, especially for only 35hp bump in power.
 

Ademuth

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Oct 7, 2015
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It really comes down to money. I realize it is an obselete system, but if I can get it running again for under a $1,000.00 that would be the way to go. If I can get two more seasons out of it, it would be worth it. Glassing and cutting the transom for merc seems to be cost prohibitive and not something I could do myself.
 

Silvertip

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Sep 22, 2003
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Just speculation here but you could do some research on the 3.8 V6 Buick engines from the late 70's. I believe the even-fire 3.8 appeared in '78 and that would be the engine of choice. Once you get into the 80's that engine would be throttle body fuel injected so you would need to do some spendy conversion or else add a carburetor style manifold. Perhaps the mounts may even be made to work with some minor fabrication. If that were made to work, you would have a nice combination. Buick also built some 4.1L V6's for the full size cars but those might be a bit tough to find. The 3.8 and 4.3 Chevy V6 had the same bellhousing pattern as the small block V8's so the drive stuff you have would definitely not mate.
 

southkogs

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Could start looking through some marine salvage businesses and see if you can locate the 225 block in good shape. I think the OMC 155 was a 225 Buick, but they were also badged Jeep. You might be able to find one easier looking at old Jeeps from the early 70's.
 
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