Cooling water pressure in exhaust manifold question
 

Have a question, I am pressure testing my cast iron merc exhaust manifolds and was curious as to what pressures do these see while running at idle or faster?

350 sbc alpha setup with thru hull exhaust. Any one have a guess? Or at what pressure do others test theirs at?

Brian

i test them at 25 lbs,that is more than they will see in the boat.

how would you test this on a 496 ho?

Couldn't you just make a block off plate with four holes in it for the riser? Or is it a dry joint, which would seem easier.....

I set up a regulator, ball valve and air hose fitting on an adapter we turned to go into a coolant hose. That way we can set a pressure and shut the valve to check for leak down.