It's all about the heads. How far are you going to go with them? Bigger valves? What kind of compression? are you going to have the crank peened or anything? You have 3.23 gears yes?
I will keep the 10.5:1 compression. The extra power will be in the heads, larger valves,port matched, bowl blended, Isky E-4 cam and the rest is stock HP273.
I have tried 2 different desktop dyno programs and both came up with about 325 hp. and as much torque at 2000 rpm. With my 4-speed and 3:23's it should run much better than the old worn out mill runs now. toolman