Wow I should have caught that with the vibration you reported at 1650Rpm. However it's a rare occurrence, and guess your previous leak issue threw me off. Only the second one I've heard of in a boat. But certainly not unheard of in the truck world. There is no rhyme or reason, power level doesn't matter, and until the L5P release, it could happen to any of them. Depending on where it broke, you might get lucky and block wasn't damaged. Then just drop in another used one and continue on. If block main journal was damaged, start shopping for a complete engine.

There is a decent / better "stock" replacement crank from Callies for about $1500. Their UltraBillet units I run require the rod big end to be thinned down, and cost about 5k. But to date, that's the only aftermarket unit which has never failed.

I've been slowly working on a conversion that will hopefully cost as little as possible. I bought a wrecked truck with an LMM and sold the transmission and TCM to cover the purchase price. I hate the idea of spending thousands on exhaust manifolds so I went to our local commercial fishing supply store and bought the only materials they had for insulating dry stacks in commercial vessels. I welded the up pipe and wrapped it and the manifold with ceramic wool and "dip lag" a fiberglass mat that hardens after its wetted. I'll sew a silicone coated fiberglass woven mat to cover this so oil and fuel won't have the chance to soak in. So far I'm 30 Dollars into this project.

Anyone have "redbeard's" contact info? I like the idea of a charge cooler that uses the hull for charge air cooling since we both have aluminum boats in cool Alaska.

I tried to post photos but I'm not allowed to until I reach ten posts.

I run hot headers in my Baja 29 Outlaw many years without any problems. 12mm copper tube, 4 pipes/header, thick aluminium folio wrap, then self made basalt cloth hood sew by kevlar yarn. I used 4 channel EGT gauge, one sensor for each header, there was 700C EGT and you can keep hand on headers. Engine room was in normal temperature also.
This design have no risk to get water in engine, they can leak only to bilge.

Hoods of picture. Aluminium folio prevent any oil get on hot header and conducts heat to copper tubes.

Maybe,when I was 16 and didnt have any money.wonder what coast guard would have to say?

coast guard would say,,whens the jiffy pop gonna be ready.

I love this! I toyed with the idea of wrapping tubs to carry away heat but never got as far as you did. The 18 year old coasties who board you seem to hardly know a thing, as long as surface temps are down you meet the regs.

Did you find other ways to save in your conversion? I'm currently wringing my hands over spending money on the oil cooler delete kit. I'd like to just use the relocation kit and route the oil return through an external cooler and save 300 bucks. How else did you save? I'm using the duramax in order to save money and weight over a cast iron conventional marine diesel so I'm always looking for these sorts of ideas.