A727 Rebuild kits redux - Rebuild kits everywhere (62-70 vs 71+)

Basic differences, the 66-70 had a 1/2 wide reaction shaft bushing(the one that's pressed into the front clutch hub) and different reaction shaft accordingly. 71-up had a 1" wide bushing, much more stable and lasts longer. Due to more stability the reaction shaft sealing rings also last longer. 71 and up also had a revised seal in the front clutch that lasts longer and seals better. 71-up had part throttle kickdown. If it's a street car it's a nice feature because torqueflite's with a shift kit are notorious for the kickdown not working good enough. If your like me and like to manual shift most of the time it's no big deal. The part throttle kickdown is a part of the valve body. I've heard you can bolt a part throttle kickdown module to a non part throttle VB but tried on one and it wouldn't fit. There are some variance in valve bodies so maybe you can on some but not others?? Again this is just a creature comfort item, not at all necessary.

BTW: To upgrade your trans. to a 71-up style all you have to do is swap in the front clutch drum and reaction shaft from a 71-73 model. Make sure you get a drum that holds 4 clutch discs, some only held 3. If you decide to upgrade to the newer stuff any later than 73 and parts interchange is hit or miss as they revised the rear clutch drum a few times and it may interfere with the reaction shaft. You could always swap out the rear drum assy. as well if you have the money. I do this on all serious high perf. applications but lower hp daily drivers I don't worry about.

The kit your looking at at CRT is a great kit but at 500 hp upgraded frictions aren't a must. I've used the kit Tony recommended and up to about 550 hp their good enough IMO, plus their more affordable.

Unless you get it for the same price there's no need to upgrade the rear band as it's not a shifting band, just a holding band. Since your going with a flex band up front I'd use a 3.8 lever. I use a 4.2 lever with solid bands only. If your using a high stall converter (2800 stall or above) another mod I do is to put a blocker rod under the accumulator. Firms up the 1-2 shift and reduces 2-3 shift overlap. Use 12 new springs in the front clutch pack. Yours may already have 12 but they loose they stiffness over time so need replaced.

Change out the rear servo to a billet piece as the factory piece is a common failure piece when a shift kit is installed.

Make sure you get a good Dacron type filter.

Get a set of planetary shims to take out the excessive play in the planetary gear set. You usually have to buy a pack of 10 and it only takes 1 or 2 but their cheap and a great upgrade. Set your rear clutch pack clearance to .040-.045". Set the front clutch to .055-.075 "clearance. Set the total end play to .020" or as close as you can get it to that.

I also drill a small diameter hole in the case to provide direct oiling to the Sprague. It's rather hard to describe easy but it's in Munroe's "727 the performance transmission" book. Running late right now but when I get home this eve. I'll scan the page in that shows it and attach it to this post.