Thinking about hooking up a late sixties three speed GM trans. to my SBC in my 40 Ford coupe and was wondering if any one out there had adapted (or tried to) the 40 column shift linkage to GM trans? Thanks.
While I have not done this exact swap, I have done similar. The shift rods are a function of a fixed end and an adjustable end to allow for final adjustments, bent to clear obstacles, with some horizontal angle at the transmission to give "shift leverage". The upper steering column linkage mates to the first/reverse linkage at the tranny. How much "throw" you want for each shift will be a function of how long the shift brackets are at the transmission. While there are mathematical equations to figure out the bracket lengths, I do trial and error. Column shift brackets usually point down on column shifts, up for floor shift.
I used a Saginaw 3 speed in my '40 pickup, along with a fairly rare 41 pu shift. You will need to make longer arms for the trans, as the shift is far too quick with the stock Chevy arms.
I've had the same transmission in my 48 Chev pickup with a floor shift for years and can't blame you for wanting to run it. I'm going to throw out a wild guess that the arms that Marty showed are Marty Built and not aftermarket.
I have a sister who is brilliant in the field of literature , has troubles balancing a checkbook , tutored her through high school & college to get her through the required math classes. We're not all good at math , no matter how much attention is paid !
Well I wasn't that good either. Think I averaged a C+ in Geometry. And trial and error in my younger years was the go to method. Since then I found Math to be an asset to solve many shop issues. However I do understand that it can be a very difficult hurdle for some.
There is a way to "cheat" the trial and error some. Starting with the column and transmission in neutral, shift the column into the third gear spot you want and secure it there. Then shift the transmission into third and see where the shift arm and bracket intersects. That will be the starting point for bracket length. Then once the 2-3 bracket is dialed in and secure, repeat the process for 1st and reverse. I have found a helper on that one is better as the shifter has to be pulled back for that.
I have a BW T85 in my 27 Modified. It was originally hooked up to column change and I swapped that for a Mr Shifter floor change kit. It was worse than useless and constantly tried to shift with both side levers, jamming the box. Over here in the UK, Hurst kits for a BW T85 are not available used and really expensive new. Given that I rarely use first gear I decided to make my own using twin sticks, one for each side lever. I had some new side levers laser cut in stainless and made my own rods using 15mm aluminium round bar and 8mm rod ends. I made the gearsticks and mounted them off the gearbox, pivoting on a shoulder bolt with wavy washers to give a preload. I made a lock-out for the first and reverse but hardly use that lever. Sent from my moto g(8) using The H.A.M.B. mobile app
Some years ago I did a whole buncha work on a kustom '49 Ford, with a nailhead Buick and a super T10 four speed. The original column linkage shifted the forward gears, the original overdrive handle shifted reverse. When all done it worked quite well- tight, positive, short throws. I'll attach a few pics. You'll have to make levers for the trans, best advice I can give you is to get them as close to 90 degrees to the link rods as you can when in neutral.
This pic is of a display chassis built by Ford to showcase changes for 1940. Look closely, you can see there's a big joggle in the 1-2 lever on the trans.
Back in the late '70s, Jerry Kugel made a quick observation: As the geometry of shift arm difference 'escaped' most, Jerry made some prototype arms (at the transmission end) for both standard and automatic transmissions, lending solution to a popular problem. These arms were adjustable in both 'clock' and lengths, as they had a milled slot for adjustment to the rods, (rod ends were spherical, so the attaching bolts could be tightened at the correct 'station') Infinite adjustment, typical of the Kugel family genius. His son(s) also. Simple? Maybe, but I was amazed.
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