Need help on a project

I just acquired a 78' Thompson trihull. It is stripped down to the bare fiberglass hull. I need to replace everything including some fiberglass repair (nothing major). First of all is the engine, it came with a 120hp 2.5L OMC GM built inline four. I need another engine and was wondering if anyone knows where I can find an engine that will fit the boat for less than $1000 including any shipping. I live near Detroit. I'm willing to go with a bigger engine if someone has one, but will then need to change out the outdrive as well. So if you know where I can find a used but good outdrive, much appreciated.

 

I didn't know Thompson built them that big!!

 

He most likely intended to say 18' and the engine is probably the 181 GM L4. This engine is very common and easily found in most any boat bone yard or repair shop. The last one I found was $500 bucks and was running the following day after new tune up parts were installed. It came with an Alpha drive attached which only needed a hydraulic line and impeller replacement. Bring a compression tester and good battery with you to the bone yard and save yourself some head banging with the guys running the place. If you don't know engines, then bring someone who really does.

 

What do you mean, built them that big? This is what I was told by people everytime I call up a marina looking for a replacement engine. If you know something about Thompsons, please feel free to tell me. I don't know anything about boats, that's kind of why I'm doing this project.

 

I have a Mercruiser 485. It is the big four cylinder. It produces about 185 HP. It will fit your drive, but may need different gears. Do you know what the ratio is now? I'm asking $900.00 for it. I don't know what shipping costs.