im building a 67 camaro which originally has a 6 cylinder on it with a saginaw 4 speed manual transmission. im not quite sure yet of the rear end ratio and the transmission ratio but according to the specifications i found on the web a 67 6 cylinder has the following:
rear end ratio: 3.08
transmission: 1st 3.11, 2nd 2.20, 3rd 1.47, 4th 1.00
so im guessing i have the same.

im gonna build a chevy 350 since I have one. will the 350 engine and saginaw 4 speed (from a 6 cylinder) work? im concerned about the ratio of this transmission and will it hold up to the bigger 350. has somebody made the same conversion? the engine will be stock performance. usage will be casual street driving.

 

It will be fine.

 

I'd run it until it breaks.

 

No such thing as a designated 6 cylinder 10 bolt/8 cylinder 10 bolt open diff rear, they're the same thing. The 12 bolt was the hi-perf option. Same goes for the Saginaw trans, it came on the 6 banger and v8's. Even the SS 350 could be had with the Saginaw M15 3 speed and the Saginaw M20 4 speed (and no I didn't accidentally mean Muncie).
Your rearend and trans will be fine as long as you don't go beating the crap out of it.

 

The M20 is a Muncie wide ratio. Thats whats in my car

M20 Wide ratio
M21 Close ratio
M22 Rock Crusher


http://www.5speeds.com/muncie2.htm

My personal experanace with the base line saginaw is it not very strong. I blew 2 of them mountain racing in my 74 and doubt I was making 275 HP. One of them I broke the case at the front bearing. Second one broke the counter gear. I am told the T-10 are as strong as the muncies.

 

"M20" is a code designation for the Saginaw 4 speed, which is what I was referring to, and what he has.
I added something to my previous post.

 

Gorn, you might wanna double check and make sure your M20 really is an M20, and not just an M20

 

Mine is a nunbers matching Muncie I never noticed they used the same RPO. No way that could cause any confusion. I am guessing the case was a big part of the weakness. I know in the later 60's GM wanted to drop Saginaw for quality issues. They retooled and fix issues and by the mid 70 was the manual of choice for GM.

 

I have the Saginaw 3 speed with my 350, that trans has outlasted 2 engines so far. Of course the 350 is only making 270 lbs to the wheels.

 

edog, how do you like having the dog-leg right 1-2 shift? I never had a 3 speed manual, is it a pain when wanting to speed shift?