What is new in B-body transmission swaps and overdrives?

Dropping freeway rpms seems to be a critical part of bringing our cars up to date. My 73' Plymouth satellite currently has a strong 727 with 3.73 gears in the back. I plan on bumping up to 4.10 eventually, but not before I take car of the transmission. I thought I wanted to go with the gear vendors bolt on overdrive, but then I found out about the A-518 swap. These are great choices, but since it's 2016, I was wondering what new options we have for swaps. Are there any modern 5 or 6-speed automatics that can be installed with minimal fabrication? Here are the options I know about:

Gear Vendors 727 bolt on overdrives:
3-speed plus overdrive (.78)
https://www.gearvendors.com/hrdodge3s.html
Minimal fitting adjustments, driveshaft lengthening
4.10 gears drive like 3.20

A-518 transmission swap
3-speed plus overdrive (.69)
http://www.cuda-challenger.com/cc/index.php?topic=84774.0
Major alterations to fit, new cross member.
4.10 gears drive like 2.83

Keisler A41 transmission swap Discontinued?
3-speed plus overdrive (.70) Electronically controlled
http://www.hotrod.com/how-to/transmission-drivetrain/0908phr-keisler-a41-automatic-transmission/
Minimal fitting adjustments, driveshaft lengthening
4.10 drives like 2.87

The late model NAG and 545RFE transmissions are physically larger but 5 speed automatics that require a computer to run. The 8 speed in the 2014 and later Chrysler and Dodge models is amazing though, First gear is 4.7 to 1. 7th and 8th are overdrive. Again, the trans needs a computer to run and as of yet, nobody has cracked the code or built a stand alone computer.
TCI had built a 6 speed automatic to fit Mopar big and small blocks. Jegs had them priced near $8500 or so !

I went with the 518 in my SB Challenger and love it.
I definitely wouldn't say it was major modifications. It was the least expensive option.
I have 3.73 gears and the OD has made the car so I don't mind taking it on 2-3hr road trips.

My calcs using a GV and 3.55 rear gears would work out to 270 something final drive...
I have 294 gears in it now.. Would love to overdrive it but probably wont happen.....
Over 3.55 gears on the street IMOP, would be overkill....

Keisler is gone but the A41 lives on here at SST!

https://shiftsst.com/articles/cat/mopar/post/charger-gtx-super-bee-1971-1974-perfectfit-kit/

Pictures of this INSTALLED???

Kiesler was great for a NO CUTTING required install that made a mess of the factory driveline angle because many Mopar owners refuse to cut anything ...

Perhaps you may want to give the 200r some consideration?

http://www.forabodiesonly.com/mopar/thre...ocation.252436/

Awesome news! Thank you silver.

Cruzin, that .67 overdrive in the 200R4 sounds very tasty.

John, I think your confusing the Tremec TKO 5 spd MANUAL withe the 4spd AOD (A41), I've done the 4spd AOD (A41) in a 71 B body with NO mods to the floor, driveline angles were within factory specs, the 4spd AOD is no larger than the TF727, the 4spd AOD (A41) was truly a "bolt-in" kit application

A41 kit is nice, real nice.. but spendy. I'll second the 200R4 route.

Here's another link for an A-518 swap into a 68 Charger. Biggest problem I see is the torsion bar cross member. It needs to be modified quite a bit. See pics:

http://www.dodgecharger.com/forum/index.php/topic,116725.msg1448658.html#msg1448658

Still only small blocks right?
Any big block automatic affordable overdrive options?

I have a GV on the 727 in my 69 Bee street car. Going on six years now and love it. I have a manual reverse VB and drive it like a four speed. 2500 rpm at 75 mph.

The Silver Sport transmission is available with either a small block or a big block bell housing. The transmissions they use have a bolt on bells.

All the other options, Mopar 500/518, GM 2004R or the 700R4 would have to have their original bell cut off and have a JW ultra Bell bolted on.

Thanks Mike , I don't know much about that auto trans and whenever I see something that came from Kiesler and had a NO HACK FIT I'm VERY SKEPTICAL after seeing a car with a Kiesler T5 and the bottom of the stock fan blade almost touching the radiator.

What are your recommendations for choosing between lock-up and non lock-up torque convertors? What situations are better for each?

Installed an A500 in my '72 Charger five years ago. It is great behind a late model 360 magnum. Put 1300 miles on it in one trip.

I drove a B-Body with a Gear Vendors. It was too little of a difference in gearing for the $, and a bother to use compared to what I have now.

I ended up using a 200R4 in my A-Body. While not cheap, the gear ratios are as close to perfect as you could get. Combined with the lock-up feature, it's like having a 5 speed automatic. Heck, I beat a Hellcat in a flag drop drag race over 300 miles from home. Next to EFI, it's one of the greatest upgrades you can do to these older Mopars.

US Cartool makes a kit to swap the transmission in, and Lonnie at Extreme Automatics can set up a 200R4 to hold over 1000 hp and it will bolt up to any Mopar engine out there including the GenIII Hemi's with the exception of the Slant 6.

Thats the one i have in the road runner now. Work pretty darn nice!!

I have 373's in the back and i am spinning 2000RPM at 65MPH or at least as close as my in dash tach says.

Ok, I am interested.