Correct, w/a 308 rear gear you do not need an OD.
But w/a OD trans you can gear it low like 373's.
I would say 411's,,, but,,,
I know it's kinda hard to fit taller & wider tires in those 65 Nova's unless you modify it.
Six cylinders need all the gearing you can get compared to a Bigger V-8.
So in my opinion, I would install 373's w/a 200R4.
Best combo to take off quick & still run great on the freeway.
I would also run a 3000 stall converter w/a lockup torque converter.
Just my two cents
Goodluck!!!
MBHD
