These little jewels have great potential. I wanted to be different by keeping a 273 and creating nice HP. Valves are from 392 hemi. Oldschool trick I learned from Ed Miller. Of course cylinders must be notched. Lunati voodoo cam with around 520 lift & matching springs. Heads ported within inch of life & Port matched offy intake and that’s rt. folks 750 cfm eddy carb on a 273. She loves it. Of course I have killed torque curve but she is a 4speed with 4.30 rear & shifting at almost 7 grand was what I wanted LOL.