2000 502 mag mpi...
 

That is the thermostat temp and what is max operating temp I thought it was 180* range I did a search but didn't find anything and I think I've asked this before but can't remember...also what is max water pressure as well...thanx...set up is in a 32 fever...

I had that same boat for 10 years. I don't know if the guages read wrong or what but, I used 140 T-stats and it ran around 160 deg.
mine had reg Bravo's with low water pick ups, none in the side.
water pressure was 35+ around 3200 rpm and above, even my perf sheet from factory showed pressure as that

This is what you need, mine have 160 thermostat, and temp range on my gauge is about 170,

i have 140 on my 454s and they run 150, ironically enough those are the only gauges i trust

Do you have carb or injected engine?

carb

140 i think , is correct for Carb engine, this is what i haved on my last boat on my 454 carb also,

but in 502mpi, its different, if i put 140 on that engine, its too cold and computer inject more fuel (choke) all the time,,

i haved several discuss in this question with many people & dealer, and in fact injected motor need to be hot more than cold, 502/500 injected come with 180 thermostat

yeah you may be right. Its one or the other. Do you know what you have in there? easy way to know what you have and how its working. Boil water and place a thermometer in the water when the water gets to 100 start holding the thermostat in the water and watch the thermometer. When the thermometer pops open you will know what temp its at.

Yes i know i haved 160 in it of my twin 502mpi, i install them myself , that why my gauge indicated 170 average

other of my friend have last year 140 on her injected 454, and after talk to me, change for 160, and save fuel now !!