The Stovebolt Site Forums The Shop Area Driveline SM 420 transmission to my 56 235 3100

Hi my 1954 3100 has a 235 w/ 848 head 1956-57 block...what would be involved in switching the B W 10R transmission to a SM 420? The BW was converted to a floor shift but the stick is not located in the correct location. I love a floor stick shift but I want to replace the BW with SM420 that would relocate the stick shift.....any place where I can find information on this kind of swap? The SM420 is suppose to be bullet proof is there another transmission out there that would give me what I want?
Thanks
Go Army

What year SM420?

Enclosed drive-shaft (as used in 1954) or other rear end? (most likely, "no").

If other rear-end, what model/year/etc?

That information is needed in order for people to give you useful/helpful information.

The drive shaft is open. The PO switch out all the running gear the engine and all else is from a 56-57 donor truck. 235 engine of course he chopped the radiator are to fit the newer 235. The transmission is an OD unit Borg Warner with floor conversion shift kit.

Thanks, Steve

I (and I'm sure several others) would trade a SM420 for that BW!

Who,Me,

The Muncie SM420 was produced by GM from 1947-1967. I had a 1964 Chevrolet truck with the SM 420 transmission that was equipped with the open drive line. If you find a later model Chevrolet truck from the late '50's to the early-mid sixties with the open drive line the conversion from the BW to the SM 420 should be fairly straight forward. If you have detailed questions you want answered contact Novak Conversions www.novak-adapt.com. They should be able to answer most questions.

Tim

What is it you want? The OD is great for highway driving. The SM420 is great for pulling stumps.

Steve,
I don't see any problems with the conversion since you have an open driveline. Have a new driveshaft built to match your SM420, cut a new hole in the floor and you have it.
The problem that I see is that you are loosing all the benefits of the overdrive with the conversion. Providing the overdrive is working it has much better highway performance than the SM420.
Considering that the stock 55-57 donor truck either had a 3:90 or 4:11 gear set, that would be your final ratio with the SM420 as it is 1:1 in 4th gear. The OD trans is .70 above the rear end ratio which is much more engine friendly on the highway.
A later T5 might be more to your liking as they have a wide range of gears plus an overdrive.
Fred

There is a perfect solution for this located here:

http://forums.devestechnet.com/foru...3-speed-floor-shifter-for-your-ad-pickup

According to Jim Carter, this would work on TF series as well. I would never get rid of my R10, but there are plenty of us willing to take it off your hands.