727 Question

[74duster]

I am having an automatic rebuilt, and have to decide between two 727s.
The first one is a 1966 and I'm told that it may not be as strong as the later models.
The second one is a 1978 lockup unit that I am told is stronger.
The difference in cost will be that the lockup unit will be about $100 more than the early one.
The transmission will be going into a 1974 Dart Swinger with a mildly built 440 and 8 3/4 rear with 3.55 gears. It is mainly a street car, but will see the track a few times this summer.
I don't know much about these transmissions, and would appreciate any advice or opinions.

 

[Ace]

There's quite a few variations on the 727 theme out there. Probably most significat year-to-year change was (From Allpar):

"On pre-1971 727s and especially hard used units, it wasn't unusual to get engine spin or flare-up during the 2-3 shift. This is more often than not turned into the loss of 3rd gear with reverse quick to follow. Chances are the steel rings sealing the front clutch retaining drum to the reaction shaft have worn themselves or the I.D. of the drum. This was probably caused because the narrow bushing in the drum allowed the drum to "wobble" on the reaction shaft causing the rings and/or drum to be worn prematurely. From 1971 on, the bushing was lengthened and a few other front clutch items were redesigned to eliminate premature ring and drum wear."

Read the full write-up here:
http://www.allpar.com/mopar/transmissions/torqueflite-tom-hand.html