Would not an AOD work with my 3.92 rear end?

 

Sure would! Depending on tire size and engine choice, it could make a really nice combination. With the .67 overdrive gear, your final drive ratio would be 2.62 in high gear.

 

Eng. is going to be 351W and tires are 275/60/15.

 

That tire is 28" tall. That should have your engine RPM at 1733 at 55 MPH. That should be enough RPM to keep the carb from slipping into the rich idle circuit in overdrive and killing your fuel economy. Go for it!

 

An AOD with that rear end ratio is a great combination...

 

With his tire size and ratio the rpm will be around 2000 @ 65.
Still real good for the Hwy.

 

Yeah, that was a typo. I meant 55 and edited it. The idea is to make sure that the engine is turning enough RPM to keep it out of the idle circuit at the lowest average speed that the vehicle will cruise at in overdrive. Overdrive in an AOD engages around 50 or so.