Restoring a non-numbers matching 68 Beaumont post - factory 275 HP 327, M20. Pulled the trans to clean up and discovered it had been swapped with an early 70s Saginaw. Looking for an M20 to install. Any leads would be appreciated.
1970 Formula 400 Carousel Red on black (std) interior 350hp, Hurst shifted Muncie 3 speed, steel wheels w/poverty caps 1:411 1970 Firebird Formulas originally sold in Canada
Did these have a different driveline combination to a Chevelle for 1968?
A 1968 Chevelle with an L30 275hp 327 (or L73 250hp 327) optioned with an M20 was a Saginaw. You didn't get a Muncie as M20 unless it was an L79 (325hp 327).
I didnt know the Saginaw was the original transmission. It appears to be. The trans in the car has been replaced and is the 3:11 first gear (two grooves on input shaft). I believe the original would have been one groove (2:56 first gear). The 3:11 was used with lower power engines in the Vegas and Monza apparently. The trans has 74 Vega written on the side from the salvage yard. Probably not the best trans behind the L30 with high rise, headers and cam upgrades). So, maybe I am looking for a one-groove Saginaw
ran into this with my 66 Beaumont 4 speed car. Because its only a 275 hp it got the Saginaw. If it was a 300 hp it would have got the Muncie. Just go ahead with your plan and find a Muncie
Saginaw is in good shape so decided to put it back in. I punished the Saginaw back in the day and it stood upplan on cruising this one so should be just fine. Learned a lot through the process of investing the M20 option code. Thanks to all the member comments.
The 2.54:1 low Saginaw was the strongest version and would have originally come on your L30/M20 Beaumont (66-68). The input shaft was the first thing to break on a Saginaw, so the 2.54:1 low used a ball bearing race just like on the output shaft. Others just used an oil impregnated bushing.
It is still a Saginaw and as such does not have the extra heft that ensures strength. Everything from the main-shaft to the syncros are lighter duty than the Muncie.
A Muncie would use the speedo cable routing through the right side near the tunnel, Saginaws go through the left side.
__________________
67 Chevelle Malibu Sport Coupe, Oshawa-built 250 PG never touched.
In garage, 296 cid inline six & TH350...
Cam, Toronto.
I don't judge a man by how far he's fallen, but by how far back he bounces - Patton
1967togo, you are correct. It is amazing how many people confuse the "M" with regard to 4 speeds. From the internet . . .
"The letter M in front of a Muncie 20 refers to the manufacturer of the transmission. The Muncie 20 is a four-speed manual transmission that was produced by General Motors from 1963 to 1974 1. The Muncie 20 was designed to be an improvement over the T-10 transmission, which was used in GM vehicles prior to the Muncie 20. The Muncie 20 was available in three different models: the M20, M21, and M22. The M20 was the standard model, while the M21 and M22 were high-performance models. The M22 is also known as the Rock Crusher due to its aggressive gear ratios and distinctive whine."
-- Edited by Pritch on Friday 22nd of September 2023 11:15:55 AM
