Hello, I'm just starting a build up on a 454 for my boat. It's a 21 foot Eliminator, with a bravo 1 out drive. The block froze over here in the mountains and I picked the boat up cheap. I'm starting with a MKIV 4 bolt block out of an 89 pick up. I have 3 sets of heads sitting here to choose from. First ones came off of the boat, second came off of the truck motor. Both of those sets are identical oval ports except the truck heads are cut out for preheating the intake manifold. The other set is the one I'm considering using. They're fresh vortec heads off of a 2000 K2500. Intake ports appear to be close to the same size, runners may be slightly larger. The exhaust ports however are noticeably smaller. I'm not looking for a whole lot of RPM out of this boat, probably no more than 4500. Thinking of a mild cam, maybe 8.5 or 9:1 compression, reasonable Holley carb and edelbrock intake, not exactly sure which ones yet. Any thoughts on these Vortec heads? I'm new to this site and appreciate any feedback I can get.