I didn't have problems with the bell housing... we need pics.

no I don't. the rear cover behind the flywheel has 4 10 mm bolts that stick out and hit the bellhousing. i just clearanced the bell.

Hmm...

I have read this tread and many others on the ls swap.
I have a ls1 out if a vette I am going to drop in my scarab jet.
I am leaning towards the carb conversion due to nobody local wants to touch a marine wiring harness and Ecu.
Plus I will be running wet exhaust so o2s are out.

With that being said. There is not a lot of room in the boat for a closed loop system, I might occasionally be in salt. What is life expectancy if freshwater wash out after every use with the aluminum block and heads? I can get creative if absolutely needed on the closed loop ( which I never have done and don't have a clue)

You can find the wet manifolds fairly cheap with the risers already set up for 02's. I wanna say that they would be about a 1k for a complete set for manifolds and risers. The gm harness and ecm are already a weather-pac set-up. Not too much to convert it for what you need. It is really just removing the unneeded circuits from the harness. There is no diff between the marine and auto stuff other than than the extra items for an auto set-up. all of the plugs, connectors, ect are the same.

I did carb on mine but looking back I wish I kept it FI. I would try and run closed cooling the ls water pump is weird cause the thermo is built it so you gotta make some set up so the manifolds get water before the thermo opens. plus you wont be able get it hot enough to run at 210. heat exchanger you can control the engine temp good.

your heater outlet hose on the water pump flows out before the thermostat then back in behind the stat. looking at marine cooling system had a u shaped hose between the two ports. this allows a bypass with a small flow area. you could feed it out the manifolds then back in for a preheater system.

OK, so I have been reading this thread, and thinking long and hard about doing a swap like this in my boat for awhile, but just never pulled the trigger. I have a 98 253 Checkmate, which currently has a 310hp 454. I have seen a best of 64mph one time, but mostly runs 59-61mph on the GPS. So obviously I want more. I have been slowly collecting parts to build a forged 454 to replace the motor with, but have just never really been too into the build. I even bought a M1SC Procharger for it, but still wasn't that excited. I am the kind of guy that likes to have something just a little different. Well after reading what kind of power can be made from these little motors, I found what i want to do!! So I went today to look at a LQ4 I found on craigslist. It had the heads off, and other than the shortblock, was mostly in pieces in boxes. But, the guy only wanted $300 for it. Welll, while I was looking I noticed another motor sitting in the corner. It was a complete LS1 with computer and everything. Long story short, I ended up with both motors for less than $1000. Left him a deposit and will be bringing them home on Sunday. My plan is to freshen the LQ4 and use the LS1 intake, TB and fuel injection set up (I like the way it looks a ton better than the truck set up). I am also talking with procharger to see if my head unit will bolt up to a LS1 bracket. If it will, awesome! If not, I'll sell my set up and buy one that will!! I am not doing this project without some sort of boost.

My main reason for posting in here is that I have a few questions. First is about the heads, more specifically, the valves. Did you replace the stock valves with Inconel valves? I'm not sure what the stock valves are in the heads and wasn't sure if they would stand up to the heat of a marine application.

EZStriper, I'll probably be getting in contact with you at some point for a MegaSquirt. Does that use the factory harness, or do you build a custom one?

This thread has already answered a bunch of my questions, but I'm sure i will come up with more. Thanks for all the info!!!

You can cut up and use a factory harness to use on the megasquirt or you can get a plug and play megasquirt to use the stock harness.

We have a custom harness on the Checkmate and the race car and haven't messed with a plug and play unit yet, but seems like a nice and easy way to go.

This is pretty much the same scenario as I'm in at the moment. I'd love to put an LSx in my Baja to replace the tired 454.

I see that your second location is Burnside. I'd love to see this project in person when complete.

Can't wait to follow your progress.