13.3's to 11.8's to Forget it...
I would use the magnum heads for a compression bump and the rpm intake. Use that 528 cam and oil through lifters. Buy the conversion kit for the heads and run cheap chevy rockers. 3500 stall and at least 3.55 gears. Or. shave the la heads .060 and .050 intake side. and run them with the same cam and the rpm intake. Wont have to find oil through lifters or rockers arms. I still don't think youll get there without some 3.91 or deeper gears but much closer.