I just posted in the wanted section for a Saginaw three speed overdrive to convert my Saginaw four speed to an overdrive. I tried going this way a few years ago, and wound up buying the wrong Saginaw three speed OD, which turned out to be a clusterfk... Also all of the conversion technical aids I had no longer will come up on my computer.. So a little help would be appreciaed. My four speed is in a 1963 Biscayne. If I remember correctly the OD unit needs to be out of a 1965 or newer ???? Would appreciate any help, as well as links to the conversion. Thanks much, Also I have searched as well as gone back to all of my previous post, but the links are all not longer available..
https://www.hotrod.com/articles/get-gone-grassroots-overdrive/ your old post https://www.jalopyjournal.com/forum/threads/adding-overdrive-to-saginaw-4-speed.647821/
There was a Hot Rod magazine article on that years ago. I believe. Somebody here will be along shortly to tell you what issue and mag. It happened before I could finish typing
Ya, me too. This is something that I have wanted to do and now thanks to you I have all of the information in one place. Of course now I can lose it all at once. Thanks anyway.
Yeah ,i thought about the same thing. You DID NOT ask for my opinion. But save your self a lot of trouble, probably money also. find a 5 speed and stick in in there.Sorry for my unsolicited opinion.
G'day, I have built a Saginaw 4 speed with overdrive and it worked quite well. At least until my dad managed to get the transmission into reverse and overdrive and the entire overdrive unit self destructed. I used a 4 speed from a 1973 Vega and a 3 speed with overdrive from a 1968 El Camino. Sorry about the OT cars but they were the sources. It was an easy swap except we were not able to get the self lockout safety for the overdrive to work in the 4 speed case. This explains the self destruction. For the two years that the transmission worked the car was phenomenal. It ran down the highway at 1850 RPM's and consistently got 48 MPG.
Actually, 1966 onward; and you already know not to try and use the old Muncie 319 overdrive transmission. PM me your name/address and I'll send you my article from 2014 in Hot Rod Deluxe magazine. GarageMotorSports.com also sells them already converted (they also sell on e-bay). I am Butch/56sedandelivery.
G'day, It was 48 MPG. I do know my math. The overdrive was not the only change made in the car. It had improved aerodynamics, was lightened by 25%, and the motor was heavily modified. It is an ot car so I am not going to explain everything I did but I did get a 4.0 with 8 college credits for doing it.
B.A. King has it right. My 63 Belair 2 door post car with a 355 SBC, 91 IROC T-5 turns 1900 RPM's at 75 MPH with a 3.36 rear. The first gear is still low enough to light up the tires. By far the easiest and cheapest way to go. Anything else would be way more expensive.
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