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Saginaw trans question

Discussion in 'The Hokey Ass Message Board' started by biscuit23, Dec 7, 2011.

  1. biscuit23
    Joined: Oct 2, 2011
    Posts: 18


    I,m wondering how much hp you could run through a saginaw 4 speed on a daily basis.
    It's in a 65 chev pick up
  2. davidbistolas
    Joined: May 21, 2010
    Posts: 962



    Saggies have a bad rep- but as long as you're not being stupid with it, it'll hold up nicely to most street motors. I was about to put one behind a mild (I'd say 350hp) 350 in my '51- but got a hold of a M21 as part of a trade deal and I'll be using that instead. Still have the saginaw, it'll find a home in something, eventually.
  3. fleetside66
    Joined: Nov 20, 2006
    Posts: 2,646


    I'm not sure if you've ever used the search function, but if you type in "Weak Saginaws" you'll find a thread discussing exactly what you're asking. There are also other threads dealing with this subject, as well.
  4. I've had a few from Chevelles and they held up fine for me. I wasn't enamored with winding it up and dropping the clutch, they won't stand up to that.


  5. jerry
    Joined: Mar 2, 2001
    Posts: 3,473


    As said above, just don't abuse it. No dumping the clutch or too hard of speed shifting and it will hold up to quite a bit of horse power.

    I ran one for quite a while before I found an M-21. Never had any trouble out of it.

  6. bobscogin
    Joined: Feb 8, 2007
    Posts: 1,761


    GM didn't put them in anything over about 200, maybe 250 hp. Over that usually got a Muncie. Of course, the operative phrase is "how much hp you could run through" it. That could be different from your full throttle output. So, I'd limit it to the power levels GM did. Also, "daily basis" doesn't mean much. If you only drive it once a year, exceeding it's capacity will still turn it to shrapnel.

  7. biscuit23
    Joined: Oct 2, 2011
    Posts: 18


    Thanks i'll do the search function

    I have and 9 to 1 small block with vortec heads that i'm putting in the truck which i'm estimating at 325 -350 hp . The truck has 3.90 rear gears with a 3 speed saginaw right now and was wondering if the saginaw could handle a bit of abuse now and then or do i look for a muncie or a richmond
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 48,326


    It should be fine if you dont go nuts on the abuse. I had to seriously abuse one behind a 396 for a few months, before I wore out second gear....
  9. they need a good shifter with positive stops and as long as you don't run slicks it should be good
  10. deeddude
    Joined: Aug 30, 2011
    Posts: 127


    It'll be fine. I ran a few behind some circle track engines and they held up ok. One engine made well over 500hp and never a problem with that one. I did break one output shaft on another, but it was abused; I ran the car in first gear with a final that calculated out to 6:53 turned it 7400 rpm every night and it final broke after about 20 nights.
    Joined: Jun 23, 2006
    Posts: 1,476


    I had a '67 4 sp in this Tbucket with a '66 327 w/ double hump heads & dual quads. about once or twice a year it would get stuck between gears. I think it was a Hurst shifter, but not sure. Also if you look real close you will see I had a very tall shifter too.

    Attached Files:

  12. mixedupamx
    Joined: Dec 2, 2006
    Posts: 513


    had a saginaw in my 72 Nova with a built inline 6cyl. used to launch at 5000rpm and power shift it (run it up to 5000 tap the clutch and ram it into the next gear without lifting my right foot) and never grenaded it! had a good MR. Gasket shifter and a HD. clutch. just my 2 cents.
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 48,326


    That's the kind of abuse I gave the saginaw I had....never let off the gas, but in addition to the big block, I had the big truck clutch in it (12"), the synchros took a real beating! and I drove it like that on the street as well as the strip
  14. Weedburner
    Joined: Nov 16, 2010
    Posts: 200

    from Wa State

    I've got a lot of real world experience blowing up Saginaw 4spds... I found the weak link in the 3.50 1st gear boxes (3 rings on the input) to be the 16 tooth input shaft. On the 2.84 sets (no grooves), more teeth on the input shaft seemed to move the fail point to 1st gear on the cluster (all use the same 29t 1st gear and 15 teeth on the cluster). The 3.11 gearsets (2 grooves) seemed to be pretty well balanced stengthwise, as it was hard to predict where they would fail. With a soft hitting slipper clutch, about 450hp was the max i could get to the ground (1.45 60' @ 2850lbs). The gears held up, but it bent the mainshaft. I had to buy earplugs to drive the car home.
  15. jrlemke
    Joined: Dec 20, 2009
    Posts: 83


    I ran a sag. 4spd w/o.d. on the back hooked to a 322 Buick nailhead with tri-power and a 4:11 rearend, in a 52 Chev., for 20 some years with no trouble. Did a lot of pounding too. -Jim
  16. Armstrong
    Joined: Apr 17, 2004
    Posts: 371


    One thing to know about the Saginaw 4-spd is if you get stupid and abuse it in reverse,you will probably only do it once.

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