Testing 454 Heads for Leaks with WATER?

[Gregski]

like Lance said use gasoline (smaller particles) and you will know right away if there is a leak rather than waiting for hours or over night

I put a large dry clean piece of cardboard on the garage floor then put something under the head when I set it down upside down so it is nice and level yet I can easily see the drip or puddle stains below

then poor gasoline from a 2 gallon red jug canister into a small glass jar (don't use a red party plastic cup cause it will eat right through it) then from the jar carefully into each chamber (oh yeah with the spark plugs screwed in of course) this way you don't make a mess and have false positives cause you missed the chambers and pored the gas all over the head

fill one chamber at a time and look under it for stains, take a pic when you see the stains so you can document which valves leaked

dirty valves with carbon deposits won't sit / seal tight so all you have to do is take a leaky valve out one by one so you know where it goes and wire push it off with a soft wire brush wire wheel then put it back in and re test if it still leaks re lap them with some lapping compound and a rubber hose on the end of a drill