have a Genv 502 that wiped out a cam lobe. I am in the process of putting it back together after boil-out and machining. would like to switch to a roller cam.which one would be a good choice? The motor still has the stock pistons, which were okay. Heads have been milled .040, stainless valves, roller rockers,EMI Thunder exhaust with short stainless risers, silent choice,800dbl pumper,stock dual plane intake.Will a Gen6 timing set with the thrust plate work with this set-up?

Gen 6 will work you will work but in the long run maybe more expensive then using the Gen 5 steel cover with a "flat face" hyd roller core.

You better check those pistons real good.
If you wiped out a cam lobe I bet you have metal on the sides of the pistons.

Welcome to the OSO forum. If you're in the market for a cam then call RMbuilder/Bob Madara of Marine Kinetics 585-654-8583 EST. For about $60 or so more Bob will custom engineer a cam for your specific application. He has helped many guys in the past few years here on OSO with cam apps.

Will the Gen VI setup (stepped nose cam and single row chain) fit under the Gen V timing cover?

That is what I would like to find out. I am a little leery about cam buttons with a stamped steel front cover.

badluck & slo poke, I used that set up on my 496 build. Works fine.

The stepped nose will fit fine. Just buy the gen 6 retaining plate and timing set. Like was mentioned above you most likely have metal throughout the engine so it needs to be cleaned thoroughly.