Author Topic: Can a Saginaw 4 speed be built to handle Big Block horse power?  (Read 8779 times)

West,J.71

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I dont know alot about Saginaw 4 speeds nor the differences between Muncie's and Saginaws. I just know that a Saginaw isnt built for high horse power like a Muncie is. My brother is looking to change his 68 Nova into a manual car from an automatic. He owns a 4 speed Saginaw and has just had a 396 big block built for his car. The prices of Muncie's on E-Bay is through the roof, is there an alternative? Any suggestions would be very helpful. Thank you

JohnZ

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #1 on: June 15, 2006, 01:17:24 AM »
Don't even THINK about putting a Saginaw behind a big-block; durability doesn't come cheap - get a '66-up Muncie with a 1" countershaft.
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West,J.71

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #2 on: June 15, 2006, 01:37:12 AM »
You made your point LOL, thank you.  ;D

hotrod68

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #3 on: June 15, 2006, 03:10:29 AM »
A Saginaw can't even handle a mildy warmed-over 327 for long! You can buy a new Richmond
T-10 (formerly Borg-Warner) 4-speed  almost as cheaply as an old Muncie on eBay. If memory serves me right, you'll have to change the clutch disc to a fine-spline, as well as the driveshaft yoke, but a T-10 is almost bulletproof. On the other hand, a Muncie M-20 or M-21 has the regular clutch disc splines and a regular driveshaft yoke. The M-22 had the fine-spline input shaft, too. The M-20 and M-22 had a 2:20 1st gear, whereas the M-21 had a 2:52, I think. The T-10 had the lower 1st gear, too--I think it was a 2:64. The 2:20s were harder to take off on with a high rear-gear ratio (3:08-3:31 etc). Hope this helps. 
HotRod'68  1968 SS350 coupe undergoing frame-off resto/rod. 386/350/4.11s
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JohnZ

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #4 on: June 16, 2006, 01:36:44 PM »
The Muncie M20 has a 2.52 or 2.56 1st gear (depending on year), and the M21 and M22 have a 2.20 1st gear.  :)
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67camarorsss

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #5 on: June 16, 2006, 08:24:31 PM »
Saginaw behind a BB? Back in the day I tore one up behind a 327 :o. Bad idea.
- 1967 RS/SS 396/TH400 (loaded clone restification)
- 1998 Z28 LS1/M6 (daily driver)
- 2002 Z28 LS1/4L60E (12 sec toy/bookend to the 67)

West,J.71

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #6 on: June 17, 2006, 03:28:29 AM »
What about replacing the gears? Is the make up of a Saginaw the same as a Muncie? Can the the inner parts swap out?  Like i said i dont know much about them but was curious.

hotrod68

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #7 on: June 17, 2006, 03:47:58 AM »
The Muncies were made to take high power and torque--nothing about a Saginaw is as good as a Muncie, West. Saginaws were weak, grocery-getter 4-speeds better suited to a 6-banger or a Vega, and they are entirely different transmissions built at different vendors. Behind a Rat, you'll shell every gear on the input shaft in short order! I'd forget the Saginaw and get a Muncie or a
T-10, or go with a Turbo 350 or 400 with a decent converter. You'll break less parts with an automatic anyway. Been there, done that. Good luck, and I hope this helps. 
HotRod'68  1968 SS350 coupe undergoing frame-off resto/rod. 386/350/4.11s
Butternut Yellow    black standard interior

West,J.71

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #8 on: June 17, 2006, 02:01:18 PM »
O.k. We've ditched the saginaw, thats going in my pick up. I'll  keep looking on E-Bay i guess to see if i can track one down for my brother. Unless anyone has one for sale here,but it doesnt look like if they do that they want to get rid of them. But thanks for the info everyone.

Steve68

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #9 on: June 17, 2006, 02:05:45 PM »
West

Look at this site.  http://www.autogear.net/   :)

Steve

West,J.71

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #10 on: June 18, 2006, 02:13:27 AM »
Thanks Steve,I've passed the website to my brother. Thanks again for the info.  :D

elesquan

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #11 on: June 20, 2006, 06:41:44 PM »
My experience with mucie's is that they are all old now, and the aluminum case expands making them much weaker than when they were new.  I had a saginaw in my '67 and did blow it up with my stock 275/327.  But I was a stupid kid at the time ;D
I had to have a muncie after that because everybody told my how much better they were.  I probably blew up atleast 6 of them in a few years.  I did find that the 1 inch countershaft mucie's did live longer.  And also, the muncie's don't shift well in higher RPM's.

I agree with hotrod on a T-10 if he just has to bang gears and blow up parts ;D

I am planing on finding a correct date coded saginaw to put back into my '67, and just drive it a little bit smarter.
So if your Saginaw has a date code of "R7C20"  I am intrested in buying it.

West,J.71

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #12 on: June 21, 2006, 01:47:43 AM »
The saginaw's #'s are GM 9164, B925656 , 1A7I87586  i'm not 100% sure but that is what it looked like to me.  I didn't see any # R7C20 on it.

JohnZ

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #13 on: June 21, 2006, 04:05:28 PM »
It's out of a late Vega or Monza.
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CamaroMaster

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Re: Can a Saginaw 4 speed be built to handle Big Block horse power?
« Reply #14 on: July 17, 2006, 10:19:33 PM »
I don't know I had a lot of fun trying to blow up a saginaw in my 68 327  and it took quite a bit before first gear blew at the worst time in front of a hole group of people I was trying to impress. I remember that night pretty well considering it was twenty years ago. Boy I was a dumb gearhead kid! I put in a m22 I stole from my old mans Corvette but he eventually stole it back and I ended up with a m20 or m21 before I sold the car like a dumb kid. Boy I wish I had that car back! oh I am still a gear head not sure if I am any smarter just have more money to spend now. LOL
68 RS
72 Chevelle
05 Z06
93 Mustang GT
67 F100
89 Toyota 4x4 p/u w 302