i have a late 80's early 90's boat with omc 4 cyl. and omc out drive. will any v6 motor mount up to it?

Question

i also need to replace the boat framing around the motor mounts, (wood surrounded by fiberglass) what is the best way to go about this problem? please keep in mind i will be doing the work myself! yes i am very handy so it won't be a problem, just need the awnsers! lol
P.S. the boat is a thundercraft.
thanks!

Answer 1

The rear bellhousing is the same but your problem lies with the exhaust. You will have to remove the 4 cylinder exhaust pipe attached to transom plate and find one for a V6 engine. Your front motor mounts may end up in a differant location which will require drilling new holes and filling old ones with marine tex.
Next your gear ratio in the outdrive will cause you to run out of RPM range, you have to change drives.
To repair stringers is a major job you will have to cut out all the rotted wood and replace it then cover it as well as the attaching points where wood ties in with fiberglass
Sounds to me like to much labor and money to spend on a 17 year old boat

Answer 2

The out-drive uses a Bell-housing to connect to the engine. Your main concern is the Bolt pattern matching or buy another bell housing that would work. Some Chevy and Fords are interchangeable, you may check with an Auto Parts store and they may have a cross reference or talk with a Mechanic that like to talk.
The other concern may be Horse Power. Some lower units are designed for a certain HP range. For example; you may notice a 120 HP lower unit may not be as big (Usually at the prop gears) as a 165 HP.

Answer 3

if you want to replace the motor I suggest you repower with a whole new (or used) unit with outdrive as well. even if you configure the mounts and intermediate hsng (bell housing adapter) the gear ratio in the out drive will be way off, and correct propping will never be accomplished you will be very unhappy with out come (seen it done before) the hp difference wont hurt the drive its just you will never get correct gear ratio!