Re: making power on 4.3
Actually no, the cam profile in the "automotive" 4.3 is bang on with the marine cam. I know because I'm running an automotive cam (and engine) in my boat.
Remember, when people talk about automotive cams vs marine cams, they used to be talking about taking a 350 out of something like a camero, and dumping it in boat. Because the camero is a sports car, it will be camed hot, to make more HP, as a result, it will make less bottom end.
But the 4.3's are ONLY used in Trucks/SUV's, so they only ever came with cams that have a pretty flat torque curve.
If your not getting anywhere near full RPM's, something's up with your setup. Like everyone said, check your ignition, and your timing, and make sure your carb is setup right.
Just for comparison, I had a 2bbl odd fire 4.3 with a 19P prop that would barely turn 4400 RPMS.
I swapped in an even fire vortec 4.3 out of a 2001 astro van (with automotive EFI, another long story) and with the same prop, I was hitting my automotive rev limter at 5500 RPMS! I ended up going with a 23P prop, and I'm still reving out to 4900 RPMS....
So in your case, I'm assuming you're grafting your old marine stuff over to your truck block: starter, alternator, intake, carbs, ignition. Because you didn't mention anything about a different intake manifold, I'm going to assume your old marine engine was vortec aswell. (vortec and non vortec intake manifolds are not compatible, different bolt pattern)
If you had a 4.3 in there originally that could hit 4400+ rpms, than there is no reason your current motor can't, so long as you can get it running right.
What vehicle (and year) did you're vortec come out of?
