408 top end changes, new trick flow heads??

Ugh. My next engine will be 12:1 on pump gas with iron heads. But I won't be using an off the shelf cam, nor anything from Bullet.

That said, I *think* you can do it IF you order the correct cam (not a big one, not a catalog cam but the correct, custom cam with the correct amount of duration and the timing set for the CR) and have your tune up dead nuts on.

An MSD 6 box would not be my choice of ignition. It better be a 7 so you can lean things at a cruise to clean it up, and still have enough ignition to fire it. And have enough ignition at idle.

And, you can't just guess at your carb. If you aren't comfortable tuning the carb, send it to someone who knows what they are doing, tell them what you are doing and let them get it close. You may have to change an idle air bleed, a main jet or something easy like that, but it will be much easier than guessing and being frustrated.

If you can do all that, I think you can do 12:1 on pump gas. Again, if you are thoughtful and careful.