Sh--!!!! Starter went THUNK!!!! Pulled plugs. #4 hole full of water. Cranked engive over to blow water out. Put plugs back in, engine ran fine! 2 days later, THUNK! pulled #4, water again. Engine is 540 BBC with IMCO exhaust. Any suggestions before I start pulling parts off?

Intake or head gasket.

Sorry, that was #8 hole.

Intake or head? Not exhaust side?

does the imco exaust have bolt on elbows? if so, go there first and replace the gasket.

Thanks Hoozey, will do that first.

Try a riser gasket first. Imco flows water through the manifold riser like stock merc iron manifolds.

That makes sense. With the angle of the engine the water ends up in #8 hole..... going to pull the riser and see if it's round or oval then order one from Imco.

Exhaust pulled and pressure tested. Imco manifold and riser is good. Pulling intake manifold Sunday. Sure hope I find a blown gasket.

Is there water in the oil?