727 performance mods

[Holeshot]

* 727 w/904 guts = less parasitic drag, + 25hp for "free".
* Torque Flite speedo gears - 30, 32, 33, 35 teeth.
* Mondello makes SFI approved flexplate for AMC.
* B&M BMM-10497 Torqueflite 727, 904, trans bkt and lever kit $ 28.69
* Use a 4-pinion REAR planetary gear for 727, standard. 727’s use a 3-pinion planetary, hemis, motorhomes, big block trucks, and turbo diesel trucks use the 4-pinion rear planetary.
* A CNC machined rear output shaft support with roller bearings is available (I've seen them on Ebay), stock is all aluminum, galls & wears the output shaft.

[FSJnovice]

The planetary idea will work for a while, then because of spline offset on the shaft (different years different taper) it will destroy itself :smile: . Insure you look real close at the spline taper before doing this and ask some of the local trans rebuilders about it also :t: . Reason I bring this up is no one likes to spend lots of money and then two to three months driving along and then have to spend more to replace complete tranny. There is articles out there on this subject a few of the car magazines have written about it. I have the article will research it and place correct info here once found. :t:

[Lifted79CJ7]

That would be awesome FSJ! I'm gonna rebuild my 727 probably in the next year or so, so any info you could provide would be greatly appreciated!!!
Jack

[FSJnovice]

mods to 727 are as follows:
In 1976 to increase strength the angle of spline teeth was changed on the output shaft it went from 45 degree internal splines on a 37.5-degree shaft there's preciious little contact area. The sharp splines act as a very efficient cutting tool, resultling in the destruction. It gets worse in 1994, the spline tooth angle changed yet again, this time to 30 degrees. This occurred also in the 727's overdrive spinoff, the A-518, as it was beefed up to accommodate the beefy new 360 magnum and V-10 torque monster cummins diesel mills. And yes you can screw up a 518 the same way.
The fix once you know it is simple use the four pinion planetary with same spline tooth angle as your shaft or swap the shaft. Just remember to use the same thrust washer setup designed for that family. For more information go to www.aandatrans.com. All this information is in the feb 2002 issue of mopar action if you can get a copy do so and read it. Story by Richard Ehrenburg page 54.