5 speed auto in a 71 dart 318

Just bought a nice survivor, 1971 dart swinger. 66,000 miles, auto on a column. I don't really want to put money into engine and paint, but 2 extra gears seems like it would make it way more daily driver/highway fun and efficient. Any ideas on a 5 speed auto for my application.

Gear Vendors overdrive. ??

Does gv have a 5 speed auto? Didn't know if there was a truck transmission that would work too? On my phone and can't search well or fast right now

IMO an A500/518 with Overdrive and Lockup comes very close to a 5-speed experience, but you'll have to be ready to do some tunnel-'remodelling' ofcourse.

You won't find any.

The new transmissions are 6 - 8 speeds, and all use electronic controls.

Maybe a 5.7 Hemi out of a late 300 with its stock transmission would fit, I believe it's a 6-speed.

There are 6-speed variants of the GM 4l80E.

Off the top of my head I can't think of a single 5-speed auto that would be found behind a V8.

R.

Just looking for options outside the usual 518 and 4 speed autos right now. I'm pulling down 25 mpg at 70 MPH on the highway and 15 in the city. More HP would be nice and shiney paint would be just as nice but no one messes with the current paint and more HP = less MPG.

a 545FE from a 5.7 Hemi is about the only bolt in option you have without doing adapter plates. A 545RFE is a "5 speed" tranny, but not how you would think. It has 2 second gears, one for upshifting and another that is between 2nd and 3rds ratio for passing gear when it shifts down. You would also need a computer to run this trans and extensive floor modifications.
As for a regular 5 speed auto, I think you are SOL.
The gear vendors unit replaces the tail shaft and gives you more overdrive gears.