If you had $2K to play with...

I don't know how "concrete" this is but just after stagecoach era I had a 225 /6 in a '64 B-Body. Shaved head 50, 2bbl manifold and carb, 2.76 to 3.55 rear end gears and lost 1.2 - 1.3 seconds ( if memory serves, slept a bunch since ) off 1/4 mile time ( 3spd manual ).