I have a place in my shop where I am collecting parts for Project X. Don't really have all of the specifics worked out. It is just items that have come along and been too good to p*** up. The stash includes an original 32 grille shell and an original 32 gas tank so it most likely will be a Deuce but who knows. Yesterday I made a trip across the big river and came back with this: Nailhead 001 by Bib Overalls, on Flickr Nailhead 002 by Bib Overalls, on Flickr Nailhead 003 by Bib Overalls, on Flickr My intention all along has been to power Project X with something other than a SBC and when I found this 1966 Buick Wildcat 401 Nailhead I pulled the trigger. In the deal, I got the matching ST/TH-400 transmission. Conceptually, I was going to use a TH-200-R4 for the overdrive gear, or possibly, a 5 speed manual. So, my question now is do I keep and use the ST/TH-400 or do I peddle it off. The only thing I really know about the ST/TH-400 transmissions is that they are stout and have a lot of parasitic drag. The "switch pitch" converter is another question mark for me. Should I keep and use the ST/TH-400 with a high gear in the rear end for cruising or should I go to an overdrive with both low end scoot and high end economy. The Buick make torque down low which seems to favor an overdrive transmission. Keeping the ST/TH-400 will save some bucks but in a light weight hot rod it may be more transmission than I need. I'm really straddling the fence right now. Is there any market for an ST/TH-400 transmission with the late Buick Nailhead bolt pattern? What is a fare asking price? What would you do?
The bottom end torque from that 'Nail Valve Spl.' will afford you to use the 400 ****** as is, and the resultant 1:1 final drive will handle a 3.0 (or 2.75) rear with ease. (unless your planned '32 weighs in the 4,500 lb. category, which is not likely) My '55 F100 pickup with SBC (350/350, '89 stage ll with 600 Holley/Edelbrock int., swirl port heads) weighs 3,000 lbs., has some steel diamond plate floor in the bed, and turns 103 in the 1/4 mile at 13.60 E.T. Freeway driving nets 17 MPG, virtually dependable, 85 MPH is a breeze for freeway driving. Ports have been carefully matched...Big difference!
One of my old girl friends mother had a new 66 wildcat convertible back in the day and even in that big old boat it would fry the tires off. LOTS of torque in that nailhead so be careful to get a strong transmission.
I wonder if you don't really have a SP/TH400 trans there. My first clue is the two wires coming from the connector on the left side of the ****** and just the tip of the bracket that mounts the switch pitch/kick-down engagement switch to the left of the carburetor. One of the wires is for kick-down and the other is to the SP solenoid. Study up on the switch pitch th400s that came in the Wildcats. Those trans have a switchable torque converter that changes stall speed and provides another approximate 2:1 torque multiplication for incredible launch power for a 4500lb Wildcat. With the 401, a switch pitch and 2.5:1 final you will have the overall ratio and mpg of modern overdrive car and still have neck snapping take-off capability.And you will never hurt it. Do a search on switch-pitch Th400, there is plenty of info out there. Additionally, I am unaware of any other automatics that will bolt up to nailheads other than Dynaslows, without utilizing an expensive adapter. That is why it is rare to see a 401 with anything besides a th400. Any Buick th400 can be made SP with the proper front pump, solenoid, and torque converter. You will want to have it in the ****** shop before you install it anyway so you'll find out if it is truly a SP. If you plan to sell it off, the only market you have is to other nailhead owners or someone who only wants the front pump and solenoid to make their Chevy housing th400 into SPs. I don't understand the parasitic drag comment however. The difference in consumed power between any of the GM V8 transmissions is somewhere between negligible and insignificant. They all have a front pump, at least two planetary sets and nearly identical topologies. I think you should start by freshening up both the motor and ******, by the time thats done the rest of a 32 may show up for you! Best Regards and good luck with all your endeavors, KB.
I used a 425 Nailhead and s/p trans. It was perfect with a 3:00 rear gear. I used a toggle switch to the trans as I didn't have the correct factory kick down. You will like the torque monster Nailhead.
Thanks guys. My understanding is that it is a "switch pitch" transmission/converter and GM called it a "Super Turbine" or ST. Based on your advice I'm going to hang on to it for now. I would hate to peddle it off only to change my mind. Still some room left in the shop.
In the one picture I can see the bracket that holds the switch pitch control switch. It must the switch pitch version. Most of these ST400 transmissions are switch pitch. If the control switch is missing just switch it manually like bangngears said or don't use it at all. In a lightweight car you won't need it anyway.
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