bayliner 2655 re-engine

[ginger ninja]

I'm looking to replace the engine in my bay 2655 due to the current lump seizing.The engine that has been removed is a 7.5 ltr omc/ford block and I'd like to replace it with a mercruiser 7.4 ltr/chevvy block. Would any of you experts out there know what would be required to carry this out...i.e do I need any new mounting plates made up ???????.... If anyone has completed a swap such as this or has any advice regarding this then please share your expert knowledge with a boating pleb....cheers

[Techteam]

You haven't given a lot to go on, I haven't done this particular one but I've done quite a few swaps. Occasionally you can straight swap but it's very rare, even car blocks can differ from the marine unit. Bolt patterns rarely match up. First check is if the drive coupling can be adapted to fit the flywheel bolt pattern. Then the flywheel housing/rear mount must be made to fit the block. OMC used both Ford and Chevy motors, the 5.0lt for instance so the parts could be available off the shelf but it would take a lot of reasearch. I drew an adapter plate on autocad and laser cut it. Sometimes the thin cover to cover the lower part of the flywheel bolted straight back on sometimes I had to make it fit, dont leave it off I was once convinced one I had done had seized after the seatrial when I tried to restart it. It turned out a loose spring washer had jammed between the flywheel teeth and the housing. Countersunk allen bolts bolt the adapter plate to the block and I drilled holes for studs for the flywheel housing and welded them in from the back. To sum up even if you own the replacement engine unless you are doing the work yourself it could work out cheaper just buying a short motor.