I have this in my turbo 200-4R and it mostly works but I've had to make a compromise. http://www.jegs.com/i/TCI/890/376600/10002/-1 The way it is set now, if I am low throttle, high vacuum, as soon as it shifts to 4th, it immediately locks up. If I go deeper into the throttle, it will mostly downshift to 3rd and that unlocks it. The only way to delay the lockup is to be pretty deep into the throttle at the 3-4 shift. If I back the switch down on the vacuum switch, it will shift into 4th then lockup, unlock and modulate until you either pull it to 3rd or just coast in 4th. I'm looking for ideas to allow a finer point on the control. Would the vacuum/intake doodad that keeps vacuum off until operating temp keep it from locking up until the engine was warm? I've considered some sort of delay box that would give me a 2-5 second count before locking up once in 4th but I have no idea how to find something like that. Any unique ideas I haven't considered? I'd like to avoid a hard on/off switch under the dash. Something like a shift lift that would keep it from locking up under 1800 RPM.
I went through a lot of the same with my 700. First issue is that the 1st vac. switch I got was defective right out of box. When I got 1 that worked, I put a vac. guage on motor and checked it at different RPM. I hooked light up to vac. switch and tested that so I could see exactly what the switch was doing at different vac. My motor makes little vac. I ended up setting the vac. real low and putting a brake switch on it so it unlocks when I hit the brake. I did also put a manual over ride switch so I could also control in manually. Before I did this, it would be fine from 65 and up, but would cycle at lower speed, 45 to 55. It does lock about a second after shift into 4th, but does unlock under partial throttle without downshifting. I looked into a delay switch, may try it one day. GM made one, but I think it was discontinued. I don't know if there is one aftermarket. There are articles on line. Search for lock up converter delay switch or valve and you will find them.
I think you will find that adding a toggle switch and leaving your vacuum switch in place will work the best for you. This way you can leave it in auto mode over ride it when you don't want the lockup. I have been driving my 91 GMC like this for 5 years. Just be sure you have a brake switch or you can stall the engine under braking.... Stalled engine = disaster with loss of brakes and steering....
You can fine tune the lock-up by changing the pressure switch in the governor port as I've shown here www.v8buick.com/showthread.php?176602-2004R-Wiring&highlight=
