How much HP

I did what is a Kind of stock rebuild of my 390 and I was wondering how much HP i got out of it. Here is what i did;

Took the stock Heads (D2TE AA) and ported the Exhaust until the bump in the Runner was almost gone. Did some light port matching on the intake side and polished the runners as best I could. I lightly ground the chambers and also polished them to eliminate hot-spots.

I have the "pop-up 10.5:1 pistons" according to my book.

I'm running longtube headers and a true dual exhaust.

I "Port matched" my stock 'T' 4V intake as well as i could with out a real shop. Currently Running a Holley 500 CFM 2bbl on it with a 2V to 4V adapter plate.

Installed a new cam and lifters @ 0 degrees.
Lift 484/510
Adv Duration 270/282
Duration @ .050" 204/216
Lobe Centerline 112 (107/117)

Any Ideas?

...I'm looking to upgrade to a Edelbrock streetmaster or old Holley single plane and a Holley or Demon 650 in the near future with a 1" carb spacer, how much HP will that bring me?