Building a 33 chev and going to use 65 401 buick . I have found the flywheel ,bellhousing , clutch etc , to make manual . I have the switch pitch sitting in my shop and a friend of mine pestering me to buy it . (has 66 ,no transmission ) .Being a floor monkey all my life ,I wonder how long my knees may allow me to depress a clutch (no problems now) ,I have put more miles on my knees ,than the soles of my feet though!!! Even though I dont want to sell ,just in case ,he is wearing me down .What do I consider replacment value or dont really want to sell price .
Can someone kindly educate me on what the "switch pitch" is? Sounds like it might change how the torque converter acts?
The torque converter has as stator with moveable blades. There's a hydraulic piston that moves them, to change the angle. An electric solenoid controls the hydraulics. The stall speed will change from about 1500 to about 2000 (with the full size 400 converter) at the flip of a switch. Using the converter from the smaller 2 speed ST300 will gain a few hundred more rpm stall. If you have the converter modified, it will stall even higher. I have one that gets about 1800 low, 3000 high. It's a ST300 12" converter.
Thanks, Squirrel! I think I understand most of what you said.... So what's the physical effect(s) one feels when you hit the switch? If I'm tooling along at 50mph and floor it with and then without the switch engaged, what difference would I feel?
Not much, perhaps one or two hundred rpm increase in engine speed. But it makes a noticeable difference on take off. And reduces creep, when you're at a stop, in gear. I usually have it in high stall when I'm stopped, or when I'm on the drag strip, and low stall the rest of the time.
whatever you can get for it. I've never paid more than core value for the switch pitch stuff I got, but it's been a while since I got it. I think values might have increased....but there is a limited market. Most guys just get a modern transmission. Being that its' one of the few transmissions that is relatively modern design, and fits a nailhead, it should be worth something.
You cant find a nailhead here ,let alone a transmission . No desire to sell other than my pal keeps pestering me about it , I may never use it, but will I ever find another ??? American made conversion kits for these are expensive 50% more and the shipping to canada ... I am just going to keep it and when I die some lucky basterd will get it off the curb where my kids left everything LOL
I'm working from memory but my 1965 Buick Riviera turbo 400 switch pitch goes "from a stall speed of 1,800 up to the 2,600-2,800 range" according to my findings in the buickperformanceclub.com site. My 425 Buick with 2 fours has 360 HP and reaches max torque of 465 at 2,800 rpm. So my car with switch pitch changes from stall of 1800 up to 2800 which is max torque so it optimizes the umph! I wired my car with the toggle switch and normally leave it to engage from the brake light switch and you CAN hear the engine rpm go up when you hit the brake! My car has the original passing gear switch still on the engine and from what I can tell it turns on the switch pitch feature at the same time it kicks in the passing gear. I need to research this some more to be sure but I do know it goes like fire when you nail it! I'm too busy controlling the beast to be certain what the switch pitch is doing! I hope this helps. BTW, I use a Hurst ProMatic Truck Shifter... it lets me ratchet up and DOWN the gears but I haven't got that completely dialed it in yet, Opportunities!!
Like you said ! Nail head stuff ain’t common around here. I would place a value of $1000 bucks on it , simply because if you ever wanted another , you would most likely have to buy a complete parts car. there is Lawrence transmissions in Rexdale that specializes in older standard and auto transmissions. He does have a huge selection of cores and is a bit of a Dyna flow and B.O.P tranny hoarder just cause they are rare-ish and guys will pay, might be worth giving him a call see what he has and what value he puts on it . good guys there and always willing to help.
Some great transmission info from you guys will keep it all in mind , by the time I am ready to drive this I may want an automatic !!!
Havent had to look for much as both engines I bought with transmissions , 63 had a dyna flow ,long gone and manual parts found . Have 65 manual parts also ... Were a lot easier to find 20 years ago
you can use the pump, input shaft (including forward clutch drum), and torque converter from this switch pitch transmission, in a BOP or Chevy (or AMC or jag or whatever) 400 case, as long as the case is old enough. I think they quit casting the extra oil passage in the case in the late 70s. You also need to add the orifice in the passage, it's a little tiny cup plug with a .030" hole in it.
There is a company in the us that make a kit to install a 700 r4 . But expensive here ,and a 700r4 is not an easy transmission to find here in Toronto anymore either ,,,,
Housings with the nailhead bolt pattern are getting harder to find. As is the switch pitch converter. I would hang onto it. Getting ready to overhaul a 64 ST400, which is a one year only thing. At least later 400 converters fit, and putting a 2800 stall in mine.
Actually the high angle of the stator is used on Buicks instead of a part throttle downshift. THM 400's without the two speed stator will downshift from high to second if you are running maybe 25 to 35 mph if you jump on the throttle quickly without flooring it. The part throttle downshift is controlled by the vacuum modulator. On a Buick with the two speed stator, it shifts the stator to high position at about 3/4 throttle. You get the same effect, more torque multiplication, without the actual 3-2 downshift. Some Oldsmobile's also had the 2 position stator. I'm not sure about Cadillac.
Cadillac used it from 65-67, I think, as did Olds and Buick. The switch controlling it was set up differently in different cars. The 65 Skylark I had with the two speed ST300 transmission had the switch in the throttle linkage, so it would go to high stall if you were NOT pressing the gas pedal, and back to low stall when you were. To prevent creep, I think. Cadillac had it set up as a part throttle sort-of-downshift.
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