First, I wouldn't buy anything ported from Indy. Plus, you don't really need to port the LA-X heads to get the power required if done like Brian's set up.
Second, you could get in the 10's as far as an engine package using a 390 stroker set up for under 6K. Look at the magazine deal Brian did with that 410. The same basic package would get you really close for an HP output, especially in a 3000-3150# car. Build it and put a 75-100 shot on it and it would be a mid tens set up in a good chassis, high tens on engine. You could save a bunch of money over the mag build shopping right for valve train (rockers), intake, carb, ignition and exhaust components.
Have fun with it. My 2 cents.