Which Trick Flow Heads with 318 (future 408)(part 1 of my plan)

I do expect to see the effective torque to shift farther up the rpm. How much gear do you have? It may be a good idea to check the cranking compression and leak down beforehand. If the numbers indicate any weaknesses, save your heads for your other build. Adding cylinder pressure with fresh heads on a worn bottom end usually doesn’t end too well. And if you use them prior to your fresh build, plan on having them gone through for cleaning and inspection before installing them on your 408. If you do get into it, though, it wouldn’t hurt to hit it with a degree wheel and dial indicator to see what cam you have and to measure the chamber volume of the heads you pull. Odds are that you’ll see a compression gain with the 60cc chambers, which is a win in itself. Whichever way you go, good luck, and keep us posted.