[aumoore]

You will end up with a 410C.I. motor with a 390 bore(4.05) and a 428 stroke(3.98). Ford did build a 406motor for the t-bird in '62 & '63 and it was rated at 385hp & 444ftlbs with a single 4bbl. the same year the best single 4bbl 390 was rated at 300hp & 427hp. This motor should be closer to a 428 in performance but it will have just a little less torque. With some Ported HiPo heads or Aftermarket aluminum heads it should put out way over 425hp.

The 390 was actually installed in a few early big block cobras and there was an aluminum block 390 in the flip top cobra. The 390 and 428 look the same as a 427 except for the side bolts on some 427 motors.