I'm running a Gear Vendors in my 70 Challenger behind a powerglide trans and Dana with 3.54 gears. Here's an old picture. This was taken with the old engine combo. It's a nice unit, but I wish the o.d. ratio was higher (it's only .78) so it only drops the rpms by about 600. With a 28 inch tire I can cruise 70 mph at 2,600 rpm.