Transmission swap

[trucksold]

I have a 64 that I’m working on fixing up. It has a 318 but a lot of the gears are chewed up so I’m looking for a replacement transmission. I’m thinking about trying to find a saginaw instead to get the sycnro first gear and maybe be able to eventually find an overdrive unit for it as well. What all might I have to modify to make this swap?

[LEWISMATKIN]

you will have to lengthen the shift rods and depending on the year model of the saginaw, you will have to reduce the outside diameter of the front main drive retainer. I hope this helps. also the slip yoke in the transmission will need to be replaced if the saginaw doesn't come with one.

[trucksold]

That’s the exact type of information I was looking for. Are you talking about adjusting the rods longer where they slide through the bracket in the column. Is there a particular Saginaw I should look for?

[LEWISMATKIN]

yes, you can lengthen them there or cut the rods somewhere in the middle. The transmission needs to be out of a truck, not a car, because of the gearing differences, even though 3rd gear is still 1 to 1.

[trucksold]

I have some follow up questions. Does anybody know what transmissions were used in a 56 Bel Air? There is a complete 265 V8 and 3 speed tranny with overdrive on Craigslist near me out of one. Would this possibly work, I know the gearing would be different. How important is that if I don’t need the low gearing of actual truck usage? Would it still be good to try and get at least the overdrive unit?

[LEWISMATKIN]

the '56 bel aire had a sm 318 transmission. Make sure you get the slip yoke with the transmission---it may not be the same. GREAT FIND!!!!!!!!

[BillT]

The '56 will have a Long Tail Shaft. Not a bad way to go, although you will still have a Non-Synchro first. Also, the Yoke will be the same (Course Splines).

Bill

[trucksold]

https://duluth.craigslist.org/pts/d/lake-nebagamon-1956-gm-3-speed/6882843999.html

Here's the ad for the one I found. Is it for sure a SM 318/319? The price feels steep, is it? Should I hold out for a Saginaw for the money? Are the overdrives interchangeable between the two?

[BillT]

The price is a little high, but they are pretty rare.

I doubt very much that you could put an early OD on a later Trans.

The newer OD Saginaw's are also pretty rare.

I heard you can put a 3-Speed Saginaw OD on a Saginaw 4-Speed though. Would love to find a Saginaw OD myself.

[sclor]

Truck sold:
The parts to verify on these transmissions are the solenoid on the driver's side and the governor on the passenger side. I would also want to pull off the side cover to see what shape the gears are in. Price may be a bit high, but this tranny should bolt in place of what you have. I have the later seven bolt side cover/ synchro first tranny in my truck. One of the best upgrades I made.
Regards
Steve
New Orleans

[trucksold]

Are you saying you went from no overdrive to no overdrive, or did you get it?

[sclor]

Trucksold
Yes I bought the transmission. It has been in my truck behind my 305 v6 and 351 v6 when I upgraded to a bigger rebuilt motor. Has worked flawlessly for eight years since I installed it.
Regards
Steve
New Orleans