Hello!! I just swap a set of Corvette valve covers for this thing, plan to put it behind a 396bb in my 55 chevy. I was told its a Muncie m22 but i dont think it is. Please help me.
I'd say that is a saginaw 4 speed, that probably came out of a low end mild v-8 or v-6 Camaro of the late 1970's. Going completely by the casting number.
paint the cast iron with silver spray paint, that'll turn it into a Muncie which has an aluminum case Strong enough for a mild 396 if you don't abuse it.
I disagree that it's not strong enough. If the car will be frequently drag raced or power shifted, maybe. For a driver hot rod while not the very best choice it's fine. Looks like you have the shifter too. I hear they're hard to come by and worth more than the trans (!).
I agree with Highlander, not strong enough for a Chevy BB apllication! There is a reason GM put the saginaw 4 speed in the "shitty" Camaro's, and put Muncie 4 speeds in High HP applications...ie:Z28
The thing that kills a tranny is the torque verses vehicle weight. a late 70's Camaro weighs about 3550 and a 55' unaltered is usually around 3350 to 3450, so as long as you don't have a blower motor or are prone to speed shifts at ten grand, it should be a very usable tranny.
yup itsa saginaw, nice street trans. last week end went parts hunt'in by a guy w/several down town "OLD" building full of fun stuff!! we were able to buy a bunch of stuff. he said "any of you guys interestd in a rock crusher, I've got the rare saginaw rock crusher, with the cast iron case!!!!! so i had to see it .......yup its a saginaw... HAA!! you very funny!!!
Saginaw transmissions are great transes. They just have a bad reputation because they are heavy, and came in low performance applications in the 60's and early 1970's. Don't believe it when people tell you that it won't stand up behind your big block, chances are, anyone who says that has never personally run a Saginaw. I had one with a 3.5 first gear (the weakest out of all Saginaws by the way) behind a mild 355 small block in a 1967 Chevelle that went 12.50's @108 on slicks launching it a 4k. It never broke. I tried breaking it for 2 years before I swapped in a Muncie that I got cheap. It then went into my 67 Camaro and it is still there and is an excellent unit.
I had a saginaw in my truck when I was a kid (17), behind a 396, it worked fine for a couple months, then I had to replace 2nd sychro...it lasted a couple more months then I put in a th400. I was really hard on it, because it was so fun to shift into second without letting off the throttle
When I was a kid I had a Firebird with a warmed up small block. I broke a Muncie in that car and replaced it with a Saginaw. The Saginaw survived longer than I kept the car. The real questions are what condition is the transmission in, and how are your going to treat it. In good condition and not abused I'd expect a Saginaw to last nicely. The same abuse that broke my Muncie is going to break a Saginaw too.
The Borg Warner T-10's have a rounded bottom line shift cover. Muncies have an aluminum case and parallel bottom line shift cover. Muncie is the way to go. The number of groves on the input splines will tell you if it's M-22 or otherwise.
Look for a 71-74 Muncie. They use the same larger diameter mainshaft and TH400 yoke as a "rock crusher" or a BW Super T-10 from a mid 70s to mid 80s Camaro, Corvette, etc. Either of those choices are stronger than an earlier Muncie and way stronger than a Saginaw.
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