The G tech tells the tale. You have what 300 gross horsepower feels like in a 40 year old 3600lbs car. The Mustang is 460 net hp, with extra gears in the transmission. You need another 100hp and more gears to equate those cars. But - the A body will turn heads. Nobody gives a **** about another Mustang.[
I built 340s over 20 years and raced A LOT of chevys and quite a few Ford's, I did not hesitate to build a 340 and put it up against any small block Ford or Chevrolet car and did for many years and was very successful at it. Had a blast racing sb mopars against more chevys than I could count. It was more expensive to set up a mopar versus a Chevy in the beginning but they lasted much longer than the chevys did . My brother raced a 4 speed 65 mustang and he sprayed and couldn't beat me. I know those were slower times but I think they were more fun than now as it was a lot harder to know how to do a good tune on a car then versus the computerized age now. MY car started at 14s and went to 9s w a steel headed, stock crank and rods 340. That's not slow for cars even now.