I have been having late shifting in my 617 (85 300Dt California) with 722.416 tranny (I think). Many of you have been real helpful, especially Brian (thanks). Here's the deal ...

I put a "T" in all the lines in and around the Vac amplifier (special to '85 617) to test vacuum (not at the same time obviously). Here's what I got:

Main Vac Supply from Booster line at amp input: 22" at idle.
Tranny Line at amp output: 17" idle, stays at 12" under acceleration all the way up tach to 4K RPM, will spike down to 5" if I stomp on the gas, and I mean stomp.
VCV line from switchover valve: 14" at idle dropping to 7" as soon as I press on accelerator and staying that way thru acceleration.
Boost line from IP area: Nuthin!! O" even underway full power.

Apparently my setup is more like a 722.3, which can be viewed here ...

www.ultrahot.com/vacuum/722_vacuum_func.jpg

This seems quacked to me. Any help you could provide would be appreciated.

** I deleted the other thread; sorry; I am with you.