Couple of 71 727 trans ?

Working on a partial 3514846 727. Listed as 383-4. It was missing pump and clutch assemblies, but planetary back all there.

The questions I have are:

The front planetary is a 4 gear, the rear is 3 gear. Is this normal, or modified at some point? Would the 383-4 trans have this?
The front servo looks like the 70 style and according to the manual the 383-4 should have the cushion style piston assembly. Also this only had the inner spring, no out spring, which the 71 SM states is 440-6 and hemi type? Was this a typical addition?

The other question I have is about shift kits. I have read through the Transgo and B&M transpak instructions. Read many post on the various forum, does some one have a document that spells out what each mod of the instruction specifically does?

The instructions really do not tell you why you are doing what your doing. Some steps can be figured out, but other not.

Example, when you drill the wall channel out with the plate, what is that doing? What does it effect? Same for some of the plate hole drilling.

Thanks,

good question about what the shift kit mods do.
i remember kunkle [i think ?] said just a week or so ago, what drilling the wall channel did, but OF COURSE i promptly FORGOT !
hopefully, he or transman will see this post and explain.
and, ..... i will WRITE the info down this time !

Generally, only the HP 440 and Hemi had 4-pinion planetaries both front and rear, the exception being when the HP 383 used the same trans as the HP 440. The 3515846 is 383 only.

The factory parts catalog is a better source of correct parts for a particular trans, the FSM is more general and not always correct.

Removing the wall from the check ball pocket creates a smoother path for the fluid that feeds the 2-3 shift valve. In stock form the fluid leaves the 1-2 shift valve, travels through the separator plate to the transfer plate, back through the separator plate to the 2-3 shift valve cavity. The direct route causes less parasitic loss.

Thank you. So it pre arms the 2-3 shift valve faster? I am assuming once flow stops pressure is equal. The kits have you remove that #6 check ball. That looks like it short out a few of the orifices between shift valve line pressure, accumulator and the shuttle valve. I guess it would equalize and pressure difference the orifices would induce?

Still not sure if this improves shift quality in any manor.

Just tracing this our using the service manual line diagrams on the vb operation.

In stock form, the apply fluid for the 1-2 shift is routed through a small orifice (the B orifice in the pic below) but the return is through a larger orifice as the check ball falls away. Removing the ball allows the fluid to flow through both the small and large orifice; this makes the shift much firmer. For a less firm shift, the ball remains and the size of the small orifice is increased.