And perhaps this fact explains why the 65 can "fry the tires" and the 66 can't.
The transmission gear ratios are quite different between the 65 and 66 4 speeds. The ratios for 65 trans: 1st-3.09 2nd-1.92 3rd-1.40 and 4th-1.00
The ratios for 66 trans: 1st-2.66 2nd-1.91 3rd-1.39 and 4th-1.00
1st gear in a 65 trans is almost a "granny gear" compared to the 66. This allows the high winding 273 engine to use rpm in place of torque to spin the wheels
If a 65 and 66 car started a race in 2nd gear, they should be about the same at the finish line.