440 Engine Rebuild advice

A 500hp 440 is not hard thats streetable mainly cos of the TF240's. The cam you chose will have 300cfm of flow from those heads which is plenty for 500hp, no need for a new 3.75 crank if your stock forged?..unit is ok. Don't even need the scat rods but not a bad idea along with the pistons for light weight but LY's will work well enough if prepped properly with good bolts unless you wanna go 7000rpm regularly which I doubt.

Intake wise an RPM is fine or even a single plain with an 850DP, 750 too small but give it a go for the velocity/torque, the sniper is not a bad idea but involves more money. Keep it simple. However a 500/512 is not a bad idea either except that if you want to be in the throttle the torque that will have will have you visiting the tyre shop every month unless you warm those DOT drag radials up before playing.

To give you an idea my old stock 440-6pk motor under 10:1CR with a Team G and an old 4781 850DP, just 260-ish cfm big valve 906 heads and admittedly a big sft cam .650/.650" made an on track 530fwhp for weight/mph. Just a few thoughts, just because all this new stuff is out there it don't mean you have to go for it to achieve what you want.