My 1995 Gen. V 7.4L 454 runs at 140ish at warm running temperature.... leaving me to believe there is a 140 thermostat in there.

It is my understanding that the 454 should run at 160, is there a downside to running at 140? Should I be concerned and swap out for a 160 thermostat?

Thanks in advance guys

I'm pretty sure that you should have a 160 thermostat in that application. 807252T2 shows as the correct part number. Running colder may not allow the combustion chamber or oil temps to get high enough for the correct burn and ability to boil off any condesation. I'd consider a 160 degree if it were me, just to be safe!

Dave

the 'old' carb'ed 454's had the 143 thermostat and would run 155-160. the newer/MPI 454's have the 160 thermostat and will run 170 ish

so if my my boat is running in the 140s, even if my 454 should have the 143 thermostat in it, should I replace with a 160 to get near the prime operating temp?

The best thing to do is to use the serial number of your engine to match up to the proper thermostat. . . Using the serial number is often the best approach on many of the model and generation specific parts.