CMG

Edward R. Cozzi

Well, first of all with an EFI/MPI engine, don't even THINK of running without a thermostat. The engine will be in a rich mode way too long and the combustion chambers will load-up with carbon deposits. They could start glowing and cause detonation.

I have seen removing the 'stats and the overheat stop, but you fixed the result, but not the cause...unless the thermostat itself was no good.

Check the risers for possibly being plugged and keeping the water in the engine too long, or you just may have a failing raw water pump impeller.
Don't forget the "Bravo Syndrome" as a possibility too.

gripit

These are 420HP's with carbs and TRS setup.

CMG

Gripit just an fyi, I replaced the thermostats twice in mine (89 454mags), new impellors and my risers were ok. I never resolved the problem other than removal.

Edward R. Cozzi

I also have seen clogged thermostat housings give similar symptoms.

gripit

So, you guys are saying that saltwater corrosion, constricting the water flow probably led to problems with overheating, therefore, the previous owner took the thermostats out. And I should probably leave them out?

Clay Washington

Whipple recommends that you remove the thermostat when you install their supercharger. I ran several seasons with a Whipple and no thermostat with ZERO problems.

Edward R. Cozzi

If it was me, I would fix it so that the engines would run at the correct temperature WITH the thermostats installed, but what do I know, I've been married 5 times!

CMG

good point
I tried honing the housing out to clear up the passages, it becomes like cement, I should have replaced them but figured it ran well withouth the therms so..

5 TIMES? I think after smashing my nuts in a vice once.....

Edward R. Cozzi

...and some people think I don't take marriage or women seriously enough!