Damn, your right! Thnx...Alex

351M, that's why I got Cleveland heads.

I have another one for you...I know I have 351C heads but the spark plugs I pulled out were 5/8 spark plugs. The C usually came with 14mm.

I lay the head on the intake side and pour water into the exhaust chamber it doesn't flow out the valves it flow out the intake chamber, but if I lay it on the exhaust side and pour it into the intake chamber it just fills it up and will not leak out.

I still don't understand how it does it?

Damn, don't say it. I just don't understand how it goes through one way but doesn't the other?!?!

I have a 78 f100 with a 351, it was sucking through the exhaust and coolant was disappearing, so I pulled the head today. Clean them up and water tested the intake and exhaust on both heads. Why does each head have one exhaust chamber that would allow the water to flow from the exhaust out the...