13" tires? I have 3:23's and a 4 speed in my 66 Dart with a fresh HP engine and can't "fry the tires" in first gear. You've got more under the hood than you think or I built a total pooch. tmm
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.