Being the weekend, I wanted to get the VB installed and the Tech Dept is closed and was hoping to find my answer here on FABO. I found a really good posting courtesy of the International Harvester truck enthusiasts forum "Binder Planet". Although referring to a TF2, a very good explanation of the orifice plug. Here's an excerpt from the posting.........
........"So everything's buttoned back up and I take it for a spin. I immediately notice a 2/3 flare up. If you don't know (like I didn't) what a flare up is, it is an RPM increase between gears. It's exactly the opposite of the issue associated with a Torqueflite transmission. They're know for a 2/3 overlap in which the kickdown band is still holding when the front clutch is applied to shift to third. Overlap is the time that both of these are holding at the same time. Eliminating/improving this overlap is the reason that Transgo kits will extend the life of the transmission. Well, in my case it eliminated it too much, I was getting a 100-200rpm rev between the 2-3 shift.
After many conversation with Transgo telling me it was lost motion between the throttle and the TV, and another site telling me I had "tired" transmission, It wasn't looking so good. Tightening the kickdown band and over adjusting the Throttle rod a little helped but didn't eliminate it and obviously I could go extreme with these adjustments. To keep the truck shifting properly I had to let off the accelerator before it shifted to third allowing the hydraulic fluid to go through the small hole in the TV instead of the large one. It would shift good this way but it wasn't right.
Well, I fixed it this morning. There is an orifice plug provided in the kit that you are supposed to drive in the Front Clutch apply hole. It slows down the fluid to the front clutch allowing time for the kickdown band to disengage simultaniously (idealy). The problem is these plugs are not a one size fits all (specifically outlined in the Carl Monroe book).
There are many factors that effect the way the 727 shifts from 2/3 but the kickdown apply lever ratio is one that can dictate the use of, or size of the orrifice plug. If you have an aftermarket 4.+ ratio, then the plug is useful as it is or it's possible that you could use even a tighter restriction, if you're running a stock or numerically low kickdown apply lever, you may need to either enlarge the orifice hole or remove it completely if you're getting flare ups.
I ended up removing mine completly and it's FINALLY shifting exactly the way it supposed to.....no bandades and nice, firm shifts.
If you are planning on installing a shift kit and want more details on a custom orifice plug tailored to your specific setup, it's outlined on page 178 in the Monroe book."