The Doug Nash I was referring to does not have an overdrive. 5th (High) Gear is 1:1. But the first and second gear are lower than your Muncie so you could run a higher rear-end gear , like a 3.08 and still have good acceleration in the lower gears like you have now, but 5th gear would drop your RPM considerably.

I have no idea what one costs new, but they have been arround for a while and if you are patient you could probably find one used or at a swap meet. They should bolt up to your bellhousing or scattershield. You will have to fabricate or move your crossmember and come up with a shifter if one doesn't come with the tranny.

It's worth a thought.

Pat