what is the best overdrive transmission for a Duster

A833 is a Truck trans and been told it won’t fit in a duster without many custom changes

I’m too am looking for a manual trans for my 318 duster . I currently have 3 on tree but thinking I want a 4/5 speed on floor but can’t find one that will fit
Look, you are confused

The A833 is not a "specific" rendition of the Chrysler gearbox. It was used in SEVERAL versions from about 63 to ?? and was used with DIFFERENT tail housings and lengths, AS WELL AS "straight through" 4 speeds and towards "the later"---the OD version

First version through --64-65..........In "big" passenger cars, long shaft, straight 4 speed, and "flange" type drive shaft connection

65--69--------B/C body cars was long shaft and slip yoke, shifter mount towards front of tail shaft
65-?? A bodies used SPECIAL SHORT TAIL HOUSING and in later years was built BOTH WITH straight 4 speed gearing and OD gearing

So far as "truck" boxes, they are simply long shaft, same as B/ C body cars

HOW TO TELL if you have an OD or straight through 4 speed box

Get the box into neutral. That is twist/ wrench the shifter shafts to the mid position until you can turn the front shaft without the tailshaft turning. Now wrench the front shaft CW, "to the right" This puts the box into 3rd gear in a straight box, or the OD gear in an OD box

Turn the front shaft exactly one turn while watching the rear shaft, after marking it somehow. If the front shaft turns 1 turn and the rear turns LESS than 1 turn, it is a "straight through" 4 speed and NOT an OD box

If the rear shaft turns MORE than the 1 turn of the front, it is an OD box.

The front shift lever on an OD box points DOWN, but someone may have mounted it incorrecting, regardless of box type.

CAVEAT!!! READ!!! There were also some oddball cases MADE FOR GM USE. Some of these had a case with the Chev bellhousing pattern, and a short GM input shaft

Example of a special GM A833 OD box.........special case with GM bell pattern, GM input shaft and special GM tail shaft. YOU DO NOT want one of these

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Another: Chrysler A833 built for GM. This time it has the GM input shaft but a Chrysler bell pattern, and was used with an adapter plate to the GM bell. This one is for a 4WD "married" transfer case

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