1970 Muncie Trans Specs

I am rebuilding a motor for my GS and I decided to get a different transmission for it. I am going to take the original engine/transmission out. I want another 4-speed muncie, but what originally came with the 70 GS's? Are they close ratio? wide ratio? Were the gears the same in all of the transmissions? I want to replace the original transmission with one that has the same specs as the original. Any help would be appreciated. I'm sure I could find this information on this website, however, I've been very busy and I don't really have the time.

Brian

 

Here is the correct 70 trans from our GSX

 

Here is pic from my 1970 GS455/4spd (Sloan documented)---mine appears
to be a "B" code which is close ratio? Pete/California

 

Brian
All Buick GS cars recieved M21 Close Ratio Muncie 4 speeds or B stamped in Muncie Case

 

That is real interesting---with a 2:20 1st gear you
really need to be hooked up to a 342 rear or HIGHER to get moving--also
clutch wear must be quicker. Pete

 

What if any were the markings on the tail? I believe my M21 to be original but my tail is cracked. Can I replace it with any tail from an M21?

 

Hi Hal -

You can replace it with a part of the same casting. Only the main case was (suppossed to be) stamped with the serial number and Muncie build information.

The tail castings varied. www.5speeds.com has all the casting numbers.

How's the car coming?

 

Torque :3gears:

I can actually start from a 'deal roll' in 4th :bglasses:

 

Thanks for all the information guys, I appreciate it. What is the gear ratio for 2nd, 3rd, and 4th gear? Please let me know if you can. Thanks.

Brian

 

All gear retios are Here

Coming to Columbus this August?

 

Marco,

I'm probably an idiot for asking, but what's in Columbus in August?

Brian

 

National Trails has the Buick Horsepower/BPG event the 1st weekend of August immediately followed by the MOPAR Nationals also at National Trails.

 

Hi Brian -

To add to Jim's post above...

http://www.buickperformancegroup.com/

 

That's where you'll see me beat the hell out of my Muncie down the track.