Great point mrfixxall. I also had a 355 and I had a Holly 780 dp and a 200hp shot of nitrous. Car ran 9.80's at 136 mph. 1.38 60ft time on a 10inch wide rear tire. GREAT engine.
Bahabob, what size boat and wheel did you spin and what was your top speed?
Thanks for all the input guys!

Stock manifolds are good for about 400HP, maybe 425.

A healthy cammed 496 stroker needs to breath. 30* of timing just aint enough for a big block.

For reference, a stock 454 420HP had 79p and 89p Secondary. My guess is if you had timing at 35* and you had piston material melting, you were too lean, not too advanced. A 850 holley will need more jet than a 750 Holley to get the proper afr. The larger venturis on the 850 slow the velocity down, and therefore dont pull as much fuel.

So, I say, up the jet sizes, up the timing to 34*. Get a good color on the plug, once you do, try 36*. Almost every marine BBC from merc had 34-38* total timing.

my 454 i was running a 23miragewith 150 drive then change the drive to136 had to go to a 21pitch mirage that was 66mph.and then i upgrade the motor to 500hp and put the 23pitch back on doing 70 . now i have a 540dart with 718hp doing 82mph. 24bravo one prop at 5800rpm .. working on more upgrades