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Questions on a 7.4 L (454) Merccruiser block

whoameye

New member
Hello all,

I am in the process of acquiring a 1989 Carver 32 Montego that has a cracked port block. This happened due to improper winterizing. It is fitted with dual 7.4L Mercs and I have been looking for short blocks so that I can rebuild the engine, but have not found a lot out there.

My question is if there is a difference on the block from a merc to a GM 7.4. I have read in a few places that the blocks are similar and in some cases can be substituted.

My second question is how to identify the generation of the engine (are they stamped? if so where?). Merc built the 7.4 that ended in 1988 and then switched their design (from what I have read). Being that the boat is a 1989 I want to insure that I am able to properly able to identify the engine. I would assume that the 1988 7.4L was used in the 1989 production MY of the Carver.

Thx 4 the help :D
 
I would never subsitute a marine gm engine with an automotive engine. The way I see it you rarely run your car at 4600-5000 rpms for a very long period of time.
 
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