got a 727 transmission i got in pieces and needed a VB for another project ,
found mods , regular drilled channel wall ,and check ball behind valve
but there was a remowed channel wall in the lower channel plate anyone now whats that for?

To clarify, does it look OE or does it look like someone added it?

Its not oe 😆

The check ball is a common mod to block the 1-2 Shift Control Valve....makes a firmer 1-2 upshift.

Drilling the partition in the channel wall is common on full manual VB's but that location isn't familiar to me; are there any other similar drillings? The pic below shows the partition drillings (shown in orange) when making a RVMB.

Nothing like your pic .i cant see any mods more then this.
5.0 lever(aluminium?) is only step from oem

In the last set of 3 pics you show this looks very similar to the B&M HotShift kit that used to be available. I had installed a couple of these in the past.

I've attached the B&M TransPak install instructions and on P2 you will find the drilling template reference location which I think matches what you show.

What I'm confused by is that the original photos you showed at the top of the screen are pointing to a different passage...so maybe just confusion on my part??? LOL

Nothing in the pics is out of the ordinary for a modified VB except for the removed partition wall in the second pic...that's a head scratcher. The steel separator plate doesn't show any mods, most kits have you drill out some of the orifices like Figure 5 in the PDF file above.

yes all ordinary exp this mod in lower channelplate , newer have seen this before in any kit , b&m , transgo etc , it looks nice machined not a hackjob

more pics ,looks like it connects to 2nd servo relese/direct feed