Reply to "what cam - lifters and rockers"

Cap'n, port stuffers do work depending on how you use the engine after adding them. Intake port stuffers behave similarly to what happens when one adds a 2V-size intake to 4V-size heads. Throttle response is much improved, mileage increases and drivability goes up... until around 5500 rpms when power drops straight off a cliff. So if you don't spend much time in that area of the tach, intake stuffers will help- especially around town.

Exhaust port mods typically do not improve power as much as work on the intake side. On a dyno, maybe 2-5% improvement at best? If you're still running stock Ansa mufflers, exhaust port stuffers may not show improvements at all, since those mufflers alone have been shown to reduce power by 50 bhp. But in some circumstances, any improvement is still.... an improvement! And they're cheap. It's been several decades since port stuffers were sorta popular and I can't remember anyone actually doing back-to-back dyno comparisons on a 351C with them. Always, the comparos were SBCs, which behave very differently.