[Terry M. Hunt]

My Turbo 400 in my '65 2+2 runs and shifts fine. It was rebuilt about 35,000 miles ago. I've always noticed how quickly the 1-2 then 2-3 upshifts occur under light throttle on level ground. I think the 1-2 shift happens at about 10 MPH. I know it's at a really low speed. I've read for years about using an adjustable vacuum modulator to raise the shift points, but I seem to recall this is only good for something like a 3-4 MPH increase. Is that correct? Is there a simple way I could raise these shift points more than this? How much more? I'm not looking to do anything radical. Just would like quicker get away from stop without having to floor it and without having to do major mods on transmission.

[ponyakr]

Some of this online info may help.

https://www.google.com/search?rlz=1C...k1.fXHmeQu48t4

[mgarblik]

The adjustable modulator will firm-up the shifts a little and raise the shift points 500 RPM or so maximum in my experience. If the transmission is in good condition and stock at this point, I can highly recommend installing the Transgo shift kit. It is not like a B&M shift kit and others that produce teeth rattling shifts at low throttle openings. It is just a nice kit that firms-up the shifts in general and delays part throttle downshifts once in high gear. I installed one following the directions carefully on my 66 421 HO wagon. It was an easy install, took a few hours. I pulled a 19ft. Sea Ray with that car and the transmission was wonderful. When not towing, the shifts were crisp and precise. I also had an adjustable modulator. I think this kit would do exactly what you are looking for. SK400 is the part number.

[U47]

I have a B&M shift kit in my T-400. The only time I get the hard shifts is when I'm in the manual mode, and no matter what throttle position. Put the car in drive and it shifts like a stock T-400. Adjustable Vacuum modulator will raise the points as said before about 500 rpm and you wouldn't want it any higher than that on light throttle because Pontiac engines were designed to make torque in the low rpm range. So use that usable torque instead of wasting it.

A FIY with you guys using a T350. I have a T350 in my 76 Olds and it's shift points were very quick, like into third at 15 mph at light throttle. I found out that GM set these cars to shift into high gear for emission reasons. The quick fix on T350 is using a T-400 stock Vacuum modulator-I did that after the car was a week old. Been in there ever since.

[indymanjoe]

http://forums.maxperformanceinc.com/...nor+adjustment Good reading here