No everything on the motor is new, carb, power steering pump, etc... The only thing I used from the old motor is the thunderbolt 4 ignition. Also this is much more horse power with a bigger cam.
Carb has nothing to do with your over heat. Or the fact you've burnt up 2 or 3 pumps. Or your low compression numbers. It mabe why you're oil smelt of gas though. You need to get the temp thing under control first is what I think. Have you got the right water pump on the engine? A serpentine belt pump flows opisite then a V belt pump. Just a thought I'm throwing out there..
One thought to consider would be if the engine is on the/a marine dyno assembly then that may help tell where the overheat issue is coming from since the engine won't be in the boat. If the engine overheats on the dyno then there's a problem with the engine/engine cooling system....If it don't overheat then you would seem to have a boat plumbing issue somewhere plus with all the engine upgrades done, might be best to just let them get it tuned right to run correctly/it's best....
If you haven't dyno'd yet take the cooling entry line and rig it to your household water. Turn it on and check your flows.
Then, once you get your engine straightened out check that your drive coolant pump is ok.