Street Killer 393w Stroker Engine Build?

450hp? haha. How's 500...easily.

AFR 205s
Crower 302HDP. 240/248 at .050", .536"/.563" if I remember correctly, and a 108 LSA. Your 393 should eat it up just fine. It's not a roller, but I had the slightly smaller brother of this cam in a 331 and with the AFRs you'll be safe to 7000. Just don't let anyone touch the valvetrain setup on the AFRs for any reason, they truly are bolt on heads, just leave them alone.
Intake, since you have 3.89s, Weiand X-CELerator or another single plane.
Carb, 750 Speed Demon.
Bottom end...this depends on if you want to do any forced induction mods in the future or maybe nitrous. Forged pistons either way, and you probably want forged rods too. Why skimp now? But an iron crank will probably do fine as long as you don't do anything crazy.
Compression, 9.5 or so, for several reasons. One, you might someday need to put cheap gas in it. Two, for the reason I mentioned above, you might get bitten by the speed bug again and want to do some FI work that would strain a high-compression engine that isn't controlled by a computer and doesn't have fuel injection.
ARP Bolts.

only 500?

I'd use AFR 205s as well.

Intake, I'd use a http://www.twminduction.com/v8_kits/v8_kits-FR.html Windsor kit.

I like quality, it's my thing, so here goes the quality adders:

Billet crank and rods and a billet steel crank girdle
Custom forged pistons for tighter top ring fit, so that the vertical gas ports do their job better, and you can run lower tension rings.
Also on these pistons: Jet-Hot low-friction coating on skirts, thermal barrier coating on crowns.

Personally I would rip the heads apart (I thought they came without valvetrain components) and get Ti retainers, roller-rockers and a nice billet aluminium girdle for each side.

Valves: coated with low-friction coating on stems, thermal barrier on heads.

Camshaft, no real idea on specs, but it would have lobes and bearings coated in some low-friction stuff as well.

I would add an oil accumulator, like the Canton one, with an electric switch, so it turns on and off with ignition, inline with an oil cooler.

For an ignition system I'd chuck in an MSD CPC (coil per cylinder) DIS.
Injection computer: Accel DFI 7

BTW, I want to build a 302 - 331 stroker with the above stuff to put in a 69 fastback with the same gearbox and diff ratio you have mentioned... nice choice

There is a lot more detail I can give you, just tell me you want it, and I'll email or pm or something.