well a 5k i had was producing about 100hp and did hi 14s low 15s in a ke20 body
it was the 1500 5k engine
the block had been bored out and had oversized pistons
the head and the block were shaved
the head was ported and had heavy duty valves springs etc
it had twin 40doce webbers on a redline manifold an accel coilpack 12mm leads 3 inch exhaust
ran timing that was beyond the advance marks on the cover (by memory it was 32 degrees advance when running on avgas, compression was in excess of 11:1)
had a 1 ton brass button clutch on the standard 4 speed and auto wagon diff and managed to lift the fronts enough to be noticable
turbo would be the better bet yet if you desire strictly old school and soemthign that draws peoples attention from the engine note alone id go na along that route
btw
there are twin cam/16v race spec versions of this engine floatign around somewhere known as the 150e
hoep that helps a bit