Jim it would be a low deck street strip car and trying to keep the torque up and the rpm down, 6500 max on the rpm, 3500 lbs and torqueflite with 3.54 gear. Heads B1 original with 2.25 headers 11 to 1 compression roller cam and NSS Indy ram intake with 800 eddys. I was thinking square 4.375 x 4.375

Getting old just means you were smarter than some and luckier than others.