Swapping out chevy 350 for GMC Detroit 6.5L Diesel

[surferguy001]

I found an add on craigslist. some guy bought three of these GMC diesels as a package deal from the military. Idk much about engines, but i do know there are marine grade and non marine grade engine parts added to the original block. This guy told me the engine came off of a Hummer, and the year is about 1988, so idk if its ok to use? Also, how much would a transom assembly and sterndrive package cost for this engine, if the engines worth it? He is selling it for $900, and im just excited cause i know diesels last way longer than gas engines. Any response is super appreciated.

O, my chevy 350 had like 1in of clearence above it in the engine compartment, would this engine even fit?

 

[surferguy001]

Re: Swapping chevy 350 for GMC Detroit 6.5L Diesel

Re: Swapping chevy 350 for GMC Detroit 6.5L Diesel

And aslo, would i be able to convert the gas tank over to diesel too?

Thanks!

 

[Bondo]

Re: Swapping chevy 350 for GMC Detroit 6.5L Diesel

Re: Swapping chevy 350 for GMC Detroit 6.5L Diesel

would this engine even fit?

Nope....

 

[elkhunter338]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

If those are the same chevy diesels they put in the truck, which coming out of a hummer I think they are I would not touch it for a boat engine.
Stick with your chevy 350 and you will be happy.

 

[TilliamWe]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

A naturally aspirated 6.5 diesel would be an absolute PIG in a boat. Your 350 is better in EVERY way. And it won't fit, and even if it did, you would be sorry.

 

[zbnutcase]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

Why would anyone swap out a great engine for one of the WORST ever made?????

 

[surferguy001]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

the 350 is rusted all the way through the entire block, and obviously has to be replaced..

 

[Don S]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

You haven't even mentioned what outdrive you have. It may not even be able to handle a diesel engine. Besides, even if it was a good engine, the cost would be way more than you think to make a diesel marine ready and hookup to an outdrive.
A new 350 engine is what you need, along with a closed cooling system.

 

[surferguy001]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

You haven't even mentioned what outdrive you have. It may not even be able to handle a diesel engine. Besides, even if it was a good engine, the cost would be way more than you think to make a diesel marine ready and hookup to an outdrive.
A new 350 engine is what you need, along with a closed cooling system.

i dont know what outdrive i had because it was COMPLETELY corroded from saltwater (think alpha 1.) It was so corroded that nothing was left basically. So i had to remove it with a sledgehammer, believe it or not, and now i need to replace everything having to do with the engine/stern. Here is a photo of the corrosion...

http://s789.photobucket.com/albums/yy173/surferguy001/Boat/?action=view&current=IMG_0473-1.jpg

 

[elkhunter338]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

I see lack of tlc, I see those outdrives covered with stuff as I walk along the docks and it is a shame to see what looks like a good boat going to waste. Yep you need a whole new setup. Might as well buy a complete engine/outdrive combo for that repair.
I wonder if the transom is solid or if it is soft?
Ever think of converting it to out boards with a off shore bracket?

 

[surferguy001]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

I see lack of tlc, I see those outdrives covered with stuff as I walk along the docks and it is a shame to see what looks like a good boat going to waste. Yep you need a whole new setup. Might as well buy a complete engine/outdrive combo for that repair.
I wonder if the transom is solid or if it is soft?
Ever think of converting it to out boards with a off shore bracket?

Its a project boat, and the corrosion came with it Lol. I already checked the outdrive by drilling some test holes and its totally solid. I just need to save money at this point cause ya, i know i need a whole new package. Huh, i didn't know i would be able to put outboards on it. I don't really want them cause they'd get in the way of the swim deck, bait tank, and trolling lines though. Aren't they way more expensive too!?

 

[surferguy001]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

Ever think of converting it to out boards with a off shore bracket?

and that would increase the slip fee too i would imagine

 

[HT32BSX115]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

Also, how much would a transom assembly and sterndrive package cost for this engine, if the engines worth it? He is selling it for $900, and im just excited cause i know diesels last way longer than gas engines. Any response is super appreciated.

Well, you could probably make it work. There is a company that does marinize the 6.5L engine.

http://www.peninsulardiesel.com/WP-PENTEST/?page_id=232

The one above is rated at 340HP and would require a diesel type Bravo I/II/III drive and Bravo Gimbal etc......

It's about the same size as a 454 BBC engine.

If you only have 1" above your SBC, you would probably have to seriously re "do" the deck over the engine to make it all fit. It also would weigh a LOT more than your SBC (about the same as a 454)


It would however, cost a fortune.

A naturally aspirated 6.5 diesel would be an absolute PIG in a boat.

Um.....ANY naturally aspirated diesel is a PIG in any thing it's in!!

Why would anyone swap out a great engine for one of the WORST ever made?????

I bought one brand new in a 94 GMC and I still have it. At almost 190,000 miles.....It still runs just fine and it pulls my 21ft Fourwinns just fine too......I think "Worst Ever Made" might be somewhat of an exaggeration.......



Your best bet might be to find yourself a newer SBC V-8 (MPI) with maybe a Bravo III or a Volvo Penta DP type drive......



Regards,


Rick

 

[Joshua Nichols]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

Why would anyone swap out a great engine for one of the WORST ever made?????

That is a good question... For the fun of injection pump replacement?

 

[Fireman431]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

That is quite a project you've gotten yourself into. Your best bet might be to find a boat with soft floors & transom just for the powertrain combo. Just swap them out together and discard the old engine/outdrive.

I noticed the registration sticker from 2001. That boat hasn't been floated in 10 years?

 

[QC]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

Hey guys . . . OP has not been back since September. Maybe he'll resurface, or maybe he decided against this

 

[HT32BSX115]

Re: Swapping out chevy 350 for GMC Detroit 6.5L Diesel

Hey guys . . . OP has not been back since September. Maybe he'll resurface, or maybe he decided against this

I just LOVE these OLD threads!!