New to me Santa Cruz repower

[Georgia]

Just joined y’all’s forum I’m glad to see someone else loves these old carvers. I have what I was told by the previous owner a 1977 26 foot carver Santa Cruz. It needs a good bit of TLC but it’s been getting it slowly but surely. Before I repaint the boat I want to drop a new motor in it it had a 351w and omc electric shift. I have gathered up all new parts as the engine was seized and the boat sat in a slip for awhile before the previous owner got it and the out drive was corroded beyond repair. I have a new out drive that I rebuilt and intermediate housing with a GM bell housing. I’m really wanting to drop my 6.2 Detroit diesel in it I’ve already sourced marine manifolds and turbo and with a turbo I still won’t be making as much horse power or tourqe as the original motor. Everyone tells me it’s going to blow the out drive up so I figured I should get a second opinion. Does anyone know what kind of fuel economy I might be looking at? Thank you for any advice or ideas y’all might impart on me!

[bud37]

Welcome to the forum.......

So the only wisdom/advice at this point would be to make sure that the hull/stringers/decks and especially the transom are in good shape before you go ahead with any refurbish. By good shape I mean free of inside rot, not soft. You may have to have the help of an expert if you are not comfortable inspecting and making the call.

Good luck with your project.....

[Georgia]

I’ve stripped it all apart and I’m not new to boats just boats of this caliber and the omc electric drive the boat is real solid and I picked it up for $1,000 from someone who couldn’t work on it due to health problems is just hate to put the motor in there and blow up a rebuilt out drive on my first trip

[km1125]

Welcome aboard!! Post up some pics when you get a chance and as you go along with the project!

I'd be very surprised if that 6.2L didn't provide a LOT more torque then the original 351 motor, but it won't be rated for as much horsepower just due to the limit on the top RPM. The torque is what could kill the outdrive though. You need to make sure you also have a coupler that can handle the torque and also absorb the torque spike as each cylinder fires, so that those don't get transmitted directly to the outdrive.

We had another member convert an outdrive boat from gas to diesel, but his was only a FOUR cylinder. His purpose was fuel economy and long distance cruising and he's been running that combo for about five years now (great thread... called something like "Little boat, big project!")

Fuel economy would have a LOT of variables, but primarily how YOU are planning to use the boat and what speeds you'd be cruising at.

[Georgia]

The 6.2 only makes about 250 tourqe and I believe the 351w makes about 300. As for the spikes as the cylinder fires that’s what I’ve been most worried about as that’s all I can see causing damage. Maybe I should talk to my fab buddies and see if we can make a something to go between the flywheel and coupler for the intermediate housing. I’d hate to wipe the ball gears out too often. I’ll have to look up his post and see if he can impart any wisdom on me! And as far as how I’m going to be driving I want to be able to plane out and back off just enough to stay on plane to get to my fishing spots but I’d say 80% would be trolling speed. My outdrive currently has 1.55/1 gears I believe and I just saw that GLM sells a 1.85/1 gear set that I could buy if need be. I don’t want to haul everywhere I go but I would like to be able to get out of a storm and keep her under control if the seas get too ruff!

[Georgia]

This was the ole girl when I picked her up and brought her home any idea on what model Santa Cruz it is? I have no paperwork and I haven’t seen any tags or plaques anywhere on the boat

[plittle2005]

Great boat, owned one for 33 years, '77 to '10. The bottom is cored keel to waterline. Thump it all over, plus the stringers. Inspect the bottom skin for signs of repair, mild grounding can scrape right thru, so navigate carefully!

A diesel requires a carefully calculated and sized torsional vibration damper, and that OMC was sort of delicate, mine was! I would not recommend installing a diesel. Custom installation is tricky, expensive and time consuming. When I worked for a major marine gear manufacturer, I tested many drive packages where the damper was not correct and the gear was ruined. BIG gears! EXPENSIVE gears!

You could get back on the water so much quicker and easier if you just put an identical engine back in, re-using any salvageable marine parts. I think there are many salvageable 351's out there that could be easily majored, and give you many years of reliable service.

Any particular questions, feel free to pm me.

[g36]

Welcome to the forum and post pics as your project progresses