I put in a gearvendors OD last winter , so far I have to say it was well worth it

BigBlockMopar said

What kind of ratio's does the GV have and what speeds are you driving normally?
Reason for asking is I have a installed a A518 OD in my '73 Dart and don't come close to the rpm you are still running on the highway, even with my 3.91 gears in the rearaxle.

Click to expand...

They have a pretty high ratio for the overdrive, .78 to 1. They do have their advantages, but the leave you with a very short driveline and some potential problems for obtaining the correct driveline angle.

I've driven a B-body with one hooked to a 727, but it just wasn't for me. That particular car had driveline vibration and the overdrive just didn't drop the RPM enough for my tastes.

They are strong though.