727 Overdrive Options

[pfonda]

Curious who has looked into adding overdrive for a 727. Have a '73 Cuda with a big block, and find myself at nearly 3000 rpm going 60 on the freeway. Aside from adding overdrive (don't want to touch the rear end gear ratio), are there any drop-in 4 or 5 speed auto trannys that don't require modifying the tunnel?

Thanks,

Peter

[Katfish]

Putting in a 518 is a great mod, makes the car so much more fun to drive.
All the info you need here:

http://www.cuda-challenger.com/cc/index.php?topic=84774.0

Only 2500 RPM at 80mph now

[Chryco Psycho]

The 518 is the best option but there is no housing that will bolt to a big block without an adapter , the other good option you can add a Gear vendors OD can be bolted to the rear of the 727 & actually gives you 6 speeds  but will likely cost more . Both options require the driveshaft to be shortened as well

[pfonda]

Thanks for the feedback. I've also been looking at an A41 auto setup from SST, much more expensive I suppose, but should be a straightforward and sturdy setup.

[1 Wild R/T]

I know they work but I still can't get behind using a GM trans in my Mopar....

I have a A500 that'll be going in my 383 Challenger.... Personally I like the gear ratios better than the A518... 

[Katfish]

SST would have been the route I'd go IF cost wasn't a factor.
I couldn't see putting a $6k transmission in a car only worth $20k.
It was hard enough spending the $2k on the 518.

Either way the improvement is amazing.

[chargerdon]

SST would have been the route I'd go IF cost wasn't a factor.
I couldn't see putting a $6k transmission in a car only worth $20k.
It was hard enough spending the $2k on the 518.

Either way the improvement is amazing.

Yep, the A518 bolts right in for small blocks.   Big cost items is the new torque converter (if you have the later a518 with locking torque converter, cutting and balancing the driveshaft.   Plus a new transmission rear crossmember or a lot of work if you make your own ( I made mine).   Activating the lockup and overdrive can be as simple as a pair of toggle switches (gives you manual control) or you can see instructions on how to make a speed activeative switch.    PS, if you use manual switches you have to always remember to turn them OFF before slowing down or worse coming to a stop.   PS..  I Have purposely left the switch for overdrive on, and pulled out in first/over and it didn't hurt anything !!   But, don't do that with the locking torque converter !!!!!!!