A Honda S600 Had a 4 cyl engine with 4 carbs producing 57 hp back in the early 60's and I highly doubt those cars were 4 wheel disc brakes back then.

A 64 Mustang wasn't a real Mustang back then anyways. It used parts from a Ford Falcon and the Fairlanes including the Falcon engine. It was a new car so it had it's quirks. Back then the 6cyl 289 only produced like 101HP. I have no clue what the 8cyl had. Maybe 120hp?? Not bad numbers for 40+ years ago. Civics today don't come with much more then that. For 40 years the Honda Civic's HP ranged from 57hp to like 120hp. Give or take a few more. The Mustang is an iconic car. If it wasn't for the Mustang you would not see some cars on the road today. The Camaro being one of them. Shit in the late 60's early 70's they were already producing the Boss, and other famous Mustang cars. The 64 was the beginning. So of course it wasn't going to be a stand out at first. Those two cars are not comparable.