440 power gains/ aluminum head advantages?

As the gurus have mentioned, you REALLY, REALLY want to know where the cam is as-installed. Not a guess or dot-to-dot or whatever; but where is that intake centerline set at? It is really important because if it's retarded from where it is supposed to, the engine will be sluggish and lazy.

A quick simple test would be cranking compression values. If you post the numbers here, there are some on here who can tell you if it is reasonable.

That's where I'd start. (Note: I still have a 4260# 69 Charger with a low compression 440 (9.2:1 CR) with the old 292/.509 purple cam that ran 12.50's at 108+ with a 3200 stall converter and 4.10 gears out back. 750 vacuum Holley and CH4B intake. Your car is lighter and should be quicker than mine!)