Does anyone who ran a sprint with a 38" motor set back remember approx what length the driveshaft would be using the 10/10 coupler? thanks, ron c

Internal or External COupler?

Its the old style external coupler.

In and out box in the car?(I'm old too!)

No in & out box. Its actually a torque tube shifter.

AKA "SLIDER". I'd guesss you're into some measuring, I have one for a midget, but nothing for a sprint. Sorry! Bob!