Junkyard BEAST!

I like this build hypothesis.
Its very similiar to my own.

I could offer some input.
You will need to figure your estimated Compression Ratio.
That will require CC'ing the dish in the pistons, and the Combustion chamber of the heads you will be using.

Once you verify your CR is over 8.5:1 (stock advertised CR...btw)

I would recommend a camshaft that has a split duration grind on the Intake and Exhaust.

The Cam Card grind should read like:

224I/232E @ .050 .540"I/.550"E 112*

I would use a windage tray if you dont already have one.
I would install a NEW double roller timing chain and NEW HV oil pump.
I used a late model timing chain tensioner on my 360 to see if there were solid gains there...like more stable ignition timing....so,....food for thought.

Then, have the heads gasket matched, the intake gasket matched, and use a FULL 2.5" Dual exhaust system, and it should make over 350rwhp.

Good for mid 12's if you can hook it up and put it down.