how can I stop breaking valves

[cook1]

I have edelbrock heads on my bbf I broke an edelbrock one and now a stainless super duty pontiac. Anyone got any ideas.

[superdave013]

it sounds like some how some way you are getting water sucked back up into your heads. Red hot valves and water = failure. Maybe run water jacketed tail pipes all the way thru the transom?

[LakesOnly]

Let's hear more about your motor...especially cam spec's and compression.
LO

[cook1]

Its a stroked 460 with 9.5 to one, crane hyd roller cam{now, first time was a hyd flat tappet}.614/.637 lift 355/368 dur @.050.
edelbrock 95 cc performer rpm heads, comp cams alum roller rockers. lighting water jacketed headers. Its in a heavey boat with a stainless aa agressor jet pump runs 5000 rpm.

[LakesOnly]

Originally posted by cook1
Its a stroked 460 with 9.5 to one, crane hyd roller cam{now, first time was a hyd flat tappet}.614/.637 lift 355/368 dur @.050.
edelbrock 95 cc performer rpm heads...
368* @ .050??? You sure it's not 268* @ .050?
Where is your lobe separation?
You clay your motor??? What's your valve-to-piston clearance?
Did the same valve (same cylinder) break both times?
LO

[cook1]

Sorry about that I must still have my eyes crossed from the weekend. It has 238/246 @.050 and .614/.637 at the valve with 112 lobe separation.

[cook1]

I have heard that manely extreme duty valves are the best valves to have for a marine application. Any thoughts?

[Craig]

You might get some different opinions on manufactuers, but you can't beat a good severe duty intake and an Inconel exhaust.