6.5 gm

[nauti dreams]

I was just wondering if anyone has a gm 6.5 or amg 6.5 or even the 6.2. If so how does it perform? What out drive do you have or recommend. Thinking about this for a 220 overnighter.

 

[fwebster]

Suggest you contact Peninsular Diesel. They offer marine conversions for the 6.2 and 6.5 GM. Due to lower RPM's with the diesel engine, you will likely need a different ratio outdrive as well as a different fuel system and a fuel return. Even though the engine itself is a bolt up, this isn't usually a low cost swap.

 

[Lazy Daze]

I have one in my Suburban, but that's not really what you're after . I'll second Frank's recommendation for Pennisular... along with the amount of work that will be needed to get it up and running. Another thing to consider is the weight of the engine vs the size boat you want to put it in. I love diesels, but personally, I wouldn't put that engine in that boat. It's a torquey engine, but it's not vastly different than a 454 - and the 454 can rev higher. Even a 350, possibly stroked to 383, would be a good choice - and easier/less costly all around.

 

[nauti dreams]

I'm very familiar with Peninsular and already have a 6.5 its an updated amg block and heads. I am aware of what all I need just wondering how a slower turning torque motor would do. I know the gears would be different but what drive? Bravo?

Looked up the weights and I would be adding at least 300lb from 302 to the 6.5 Not sure I want to do that until I see how she sits in the water.

I already own the 6.5 and its new sounded like a good idea and easy on fuel. I'll run the 302 around a bit with some sand bags and see how it rides.

 

[fwebster]

300 lbs is like 2 adults sitting on the back seat. I don't know about the waterline, but
if you pick a 285 hp to 300 hp configuration of the 6.5 GM then couple it to a Bravo drive, it should be a nice running boat.

You will need to work backwards from the WOT rpm on the diesel to compute the gear ratio and prop pitch you'd need.

I've owned a turbo version of the 6.5L GM for about 20 years and they are great engines. They do not tolerate overheating so rather than converting a truck engine I think a Peninsular marine conversion with heat exchangers and bracketry might be a better approach. The other thing to keep in mind is that the 6.5 is not that economical in higher rpms ranges, but they have excellent economy in the mid range and that mary affect which horsepower version you choose as well as the gear ration in the outdrive.

Good luck with it….sounds like a fun project.

 

[nauti dreams]

Thanks. I would convert this one its the same block and heads they use just need the bolt ons. It also has ARP head and main studs as well as a girdle kit to strengthen the bottom end.
I am unsure of the current water line but this will be a project for later. I already have a new 302 so going to enjoy that for now. Thanks