I have a 1964 special that I am rebuilding. I was originally going to be running a 340, but after purchasing one a came across a great deal on a 455. The car will be a weekend cruiser and show car. I will not be hitting the strip with this car. It currently has 3.08 gears but I will be stepping up to a 3.55 or 3.73. The motor is mostly stock, except for carb, edelbrock performer intake, and before it lands in the car it may get a very mild cam. I have a st400 already (may need to be gone through), but have a friend selling at th400 out of a 72 electra (long tail shaft) with around 40k miles on it and it shifts good. He wants $150 for it. Would i be better going that route or using the st400 for what im wanting to do with the car? I know that if the st400 needs to be rebuilt it will cost more that $150 but if its worth it than i would be willing to spend the money.
I have the best of both worlds, a later TH400 case and internals converted to variable pitch from parts of the original '67 ST400. I don't remember the details, but there were some advantages to the later parts, one being the newer center support and center support snap ring the earlier transmissions don't have. I think the valve bodies have some updates that are also preferred if you retain automatic shifting. Maybe some others can chime in with better detail. Devon
The switch pitch valve bodies have calibrations that that mean an early shift to 3rd despite the governor. They also have no 3-2 valve, so only have a full throttle kickdown. All that can be remedied by swapping in a later model valve body. Read more here: http://www.buickperformance.com/SPTrans.htm I highly recommend keeping the ST400. The switch pitch is an awesome transmission for a car that is mostly street with some strip action.
Thanks for the input, my st400 is out of a 67 skylark gs...not sure it they had a better calibration or not. Since I will be running a holley carb will I have difficulties with the linkage?
Are you planning to use the '64 switches to control variable pitch and detent? I'm familiar with the '67 switches beside the carb and on the throttle linkage itself, and when I used a Holley squarebore carb on an Offenhauser intake I had to lengthen the rod on the plunger switch and add a ball on the Holley throttle shaft bracket to accept the rod. If you're running a Quadrajet on the 455, you'll have to look at the '66 or '67 to see how the linkages attach. I have the attached '67 pics, but they don't show detail without the air cleaner. Devon
I was planning on using the 67' switch since i dont have the 64' switch. I have also read something about installing a switch in the car that can be manually controlled? Is that a good option? If so, does that eliminate some of the linkage issue?
That's what I have set up. There are two separate switches that control hi/low stall. (See http://home.comcast.net/~shinzan/ST400_linkage.jpg) One is a microswitch on the firewall linkage that energizes the stator solenoid to high stall whenever the throttle is closed. This really helps smooth the idle at a stoplight. See view "B". The bigger switch at the side of the carb has two functions. It energizes the stator solenoid at about 2/3 throttle, and also energizes the detent solenoid (kickdown, downshift, passing gear, etc.) at 3/4 throttle. See view "C". If you still want the detent function for passing gear, you'll have to keep using the stator/detent switch at least for that, but there's no reason you can't run a momentary switch on your dash or shifter to get high stall whenever you want. I don't use the stator/detent switch anymore since I run a manual valve body and have no "passing gear" unless I downshift manually. I have a small momentary switch on the shifter for high stall on demand, and I still run the small throttle switch in view "B" for high stall whenever the throttle is closed. If you'd rather handle everything automatically, Bruce Roe sells an adjustable electronic timer. See http://www.v8buick.com/showthread.php?t=190075 and http://www.v8buick.com/showthread.php?t=190075 . Personally, I love having the momentary switch available. Devon
So if i use a momentary switch instead does that eliminate the switch on the linkage?(basically running standard throttle linkage) I like the idea of manual control.
You could do that, but if you delete the plunger switch entirely, you lose transmission detent (downshift) unless you arrange something else. Devon
Controlling the stall is really very simple. If you remove the wire that leads from the plunger switch down to the transmission, and then wire a momentary switch in, you can control when you want high stall. One end of the switch goes to the transmission, the other to a key on 12 volt source. You could mount the momentary switch to your shifter handle.
As long as the momentary switch is wired parallel to and not in series with the idle high stall switch, you can retain the idle switch's function as well. Devon
Spoolin, Keep the 3.08 gears...perfect set-up for all around performance......install a posi unit and you will be set.
