Shoot.... just check that the valves are sealing, if not lap 'em. Your cam isn't THAT big. If those springs that came with those heads won't take a .520 lift, then Chopsticks to lamb chops! I say run 'em!
There you go panning for that disagree button...
I was saving up for the big answer I had to eat dinner...
I'd skin the cat your way if it was some junkyard 318 or 360 but it's not...
I'll be disassembling and checking the spring rates you can Bank on that...
Not saying I won't put it all back together and run it, just I will check things out. It's basically free to take them apart and take them down to a shop..
Anyways don't you have a van to buy...
