also asked this in the Drive section but it fits better here.

I'm thinking of using a 97 vortec 454 in a boat. What are the stock cam specs vs the 330hp marine cam specs. What is the largest cam the stock l29 heads can handle without changing the valve springs?

I've always heard than marinizing a car\truck motor ends up being a wash at best, but I'm curious to see this go round again.

Ok, think I got it.

Truck gen 6 vortec specs
204/209 duration
480/483 lift

Gen 6 vortec marine
224/224
483/483" lift

stock valve springs good to .500"

can any body confirm?

Sort of,

People on here are running .550"+ lift with apparently no problems at all on stock lifters in a Gen VI block.

The heads respond well to lift and duration due to their small chamber but also small valves. To work them you need to smooth the inlet tract and if you really want them to shine, put larger valves in (2.19" and 1.88")

I'm have a Crane 731 with .587 and .610 with the longer lifters but that's just to be safe. The springs in the truck vortec are weaker than the marine too, not sure of the spec dif, but the truck vortec ran about 8:1 comp and the marine about 8.5:1 comp somehow (apparently).

You'd probably get away with about .323 which is .549 with 1.7 rocker looking for duration @.050 of 230/236. That's guessing for stock truck heads and springs though, I wouldn't push past that at all.

You will have to replace the stock automotive valve springs with marine grade. Simple reason is marine engines run often at a sustained higher rpm say 3000 - 3500 and automotive springs are really designed for about 1700-2000 sustained. Also the valves need to be severe duty, again not used in automotive. Lift of .500 or less will be fine.

Wannabe