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Author Topic:   Saginaw or Muncie, what do I have?
Speed Racer X
Dirt Full Roller

Total posts: 61
posted November 24, 2002 09:58 PM
This weekend we removed the 3 speed transmission, bellhousing, clutch assembly and flywheel from a 1973 Chevy 1/2 ton pickup with a 250 inline 6. The transmission is cast iron,mounts to the bellhousing with 5 bolts, and the side cover has 7 bolts. It is not marked with a brand other than GM and some casting numbers. It has no lines on the input shaft. I'm assuming that we have a Saginaw with a 1.68 second gear. Am I correct??? Thanks

tilley88
Dirt Freak

Total posts: 353
posted November 25, 2002 08:34 AM
The ratio sounds right, but I'm puzzled by the "5" bolts on the bellhousing mounting. Is there one in the middle on top?

Speed Racer X
Dirt Full Roller

Total posts: 61
posted November 25, 2002 04:46 PM
Yes it has the 4 bolts like normal, plus 1 right on the top of the transmission. Thanks!!!

BK19
Dirt Freak

Total posts: 285
posted November 25, 2002 04:49 PM UIN: 40696038
is it a really small tranny causei know they had a really small saginaw in the pickups with the 6 cyl that is different then the normal 3 speed saginaw, i dont know if they will work in racing i have never use one

ford5
Dirt Freak

Total posts: 298
posted November 25, 2002 06:04 PM
i'm sure it is a saginaw 3 speed, i have seen them with that extra '5th bolt on top' it will work just fine for racing. you dont have to use that hole if u dont want to.
ford5

tilley88
Dirt Freak

Total posts: 353
posted November 25, 2002 11:53 PM
Being a '73 model, It's not the Potbelly Saginaw. Probably not the 1.75 cast iron Muncie, either. Good luck with it!

rico 08
Dirt Freak

Total posts: 372
posted November 26, 2002 01:54 PM
you need to"count the turns"to check the ratio it could also be a 1.76.some of the older cars/trucks also have a 1.88.

avila
Dirt Full Roller

Total posts: 55
posted November 27, 2002 06:11 AM
Here is another way to tell if it's a saginaw or muncie


type = m)uncie, s)aginaw

type years side cover id case id case length application
bolts
---------------------------------------------------------------------------
m318/319 '55-68 4 cast iron 7-1/8" --

m330 '69-78 7 cast iron 11" fully sync'ed

s326 '66-+ 7 cast iron 9-5/8" fully sync'ed

Saginaw 3 speed, grooves cut into the splines of the input shaft:
grooves run perpendicular to splines, all the way around the shaft.

0 Line 2.85-1st, 1.68-2nd, 1.00-3rd
1 Line 2.54-1st, 1.50-2nd, 1.00-3rd
2 Line 3.11-1st, 1.84-2nd, 1.00-3rd
3 Line 3.50-1st, 1.89-2nd, 1.00-3rd

Speed Racer X
Dirt Full Roller

Total posts: 61
posted November 27, 2002 11:31 PM
Thanks, The side cover measured 9 5/8 inches and there were no groves on the input shaft, so I must have a Saginaw with a 1.68 second gear. Thanks again for all the help!!!

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