I know that some of the sags with 311 low gears were put in the vega cars back in the early 70's, but not sure what else they were used in. I took a few out of those old vega cars and used them behind v-8's, but never raced them. They had the low first gear to get the 4 cylinder car moving because they had low powered motors. I even know of one a friend of mine put behind a v-8 in a old school bus because it had the low first gear. I was told that they were weak trannys, but never knew anyone to blow one up. Does yours have a funny looking flang under the back side of the tranny with three holes in it? All the ones i had did. It was there to put a counter weight to do something. Saw some others that didn't have that weight bar, but they were in other types of cars. I even had one of those behind a 63 nova 6 banger. It realy helped alot with that motor. If you run 3.08 rear gears, with that tranny, you should have about a 9.50 final gear ratio, which isn't to bad. Still have a 77 nova today that i bought new. With 3.08 gears, you should be able to drive it with highway use in mind.

 

I really didnt plan on racing it but i thought since i had old dirt track stuff around might as well use it. i know that the cam is pretty big for a street car but i thought since it doesnt hit the power band until3200 it would lose enough low end torque that it wouldnt hurt the trans. having said that i dont think a 3.08 will have enough to keep it up in the rpm where it needs to be in 4th gear but i really aint sure. and yes mine came from a vega and it haa the shifters and that balance thing and i dont know if i need that or i can remove it or what its purpose is all together

 

I ran the same tranny behind a stout 350 and never had a problem. I had a 3.70 gear in the back. Luved the 3.11 first gear though. Super easy to get her rollin' with the big cam I had in it. Ran about 2800 rpm at 70 mph. You couldn't even think about windin' her up and side steppin' the clutch unless you liked walking!
Once she was rollin' I never had a problem speed shifting it. You gotta know the limits!!
Actually ran the same tranny behind a 396 for awhile. With a 3.31 gear. Same thing, you gotta be gentle!!

 

Yeh, if you got a heft cam, it maybe a little more than you want for rear gears, but i still think i'd not want to go below 3.42. I like the lower geared beasts to, but when you go to low, its hell to drive on the highway. -- The extra weight on the tail end was suppose to take the vibration out of the drive train since they were 4 bangers. I always took them off. My 77 nova concours hatchback now has 355-200-4r tranny with 3.73 posi. But the overdrive 200-4r gives me back my highway gear. I can't remember the gear spacing on the sag other than it had 3.11 low and 1.1 fourth gear. That low gear should help alot, and it depends on other factor with the motor.

 

Nuthin' fancy about the engine 11:1 comp, 461 d-humps 2.02 1.60 valves 750 vac sec holley 3.48 stroke just a basic dirt track engine. I've never had it dynoed so I ain't going to make anything up. I'm not really sure about the other two gear ratios either but I know it's not close ratioed and it ain't going down the interstate so I was thinking 3.73 or 3.89. Also has anyone ever ran one of those summit shifters. Are they easy to adjust? I know it ain't hurst but hurst didn't have my budget in mind when they built thiers. And what is the best fluid to put in it for syncro life and protection. When I was a roundy round racer and ran sag three speeds I ran John Deere Hydraulic oil. Keep the comments coming.

 

I think the 3.11 and 3.50 Saginaw 4-speeds actually had slightly narrower gears, which is what makes those two transmissions "weaker' than say a Saginaw in a Nova/Camaro/Chevelle/Vette (yes, they did come in Vettes too, just not the truly performance ones). Your engine is far too much for ANY Saginaw to to truly stand up to with any confidence. I've beat on them too, and they took it, and I've know guys who could't keep them together for very long. Same guys also could't keep a Muncie alive. If you drive it in a way respecting it for what it is, it will last; if you disrespect it, well......................... I think if you look at the vehicles GM put them in, engineering makes some sense; they did'nt put them behind hi-performance engines for good reason. Just my 2 cents. Butch/junior stocker.

 

I think your right JUNIOR, That rings a bell as being corrrect. I know I ran narrow tires which I'm sure helped it live behind a v-8. It gave it a little spin more than usual, but leaving rubber marks never bothered me emotionally. The first year or two of the vega, they used opel parts which didn't help, then they used sag trannys. The best part of the vega turned out to be the sagina.

 

I've broke many a Saginaw 4spd, but i was always able to drive it home from the track (about 85mi). I might of only had 4th gear or no 1st gear, but was always able to drive it home. There's plenty of room for broken teeth to lay on the bottom. I never twisted off an input shaft, never broke a case or tailhousing, never broke a mainshaft. I have bent mainshafts though, which required wearing earplugs for the long ride home.

Here's a list of Saginaw 4spd input/cluster tooth counts (the front set of gears in the box)...

2.54 ratio = 19/25
2.84 ratio = 19/28
3.11 ratio = 18/29
3.50 ratio = 16/29

All Saginaw 3 spds and 4spds use the same 29 tooth 1st gear and same 15 tooth 1st gear machined on the cluster. The different 1st gear ratios were due to different tooth counts on the input shafts and the front gear on the cluster. Lots of input reduction (small input shaft gear) made the front of the box weaker, the stronger 19 tooth input shafts moved the weakest point to 1st gear on the cluster. Keep in mind that all Saginaws use the same 1st gears, the weak point inside the box just moved because the 19 tooth input shaft was stronger.

2.54 and 2.84 ratio boxes shelled the teeth off of 1st gear on the cluster, 3.50 ratio boxes shelled the teeth off of the input shaft. The 3.11 gearset seems pretty well balanced strengthwise, as I couldn't predict which teeth would break.

My best 60' was 1.45, but that car/driver only weighed 2850. It did have 275/60 drag radials and got 4500rpm clutch dumps, but it also had a lite 17lb flywheel and a hydraulic slipper control on the clutch pedal. 3.73 gears out back.

If you have synchros, GM Synchromesh is about the best for quick shifts. Anything any slicker will slow things down, as the synchro has to grab the gear enough to slow down not only that gear, but the cluster/inputshaft/clutch disc as well before it will actually go into gear. The heavier the clutch disc, the harder it is for the synchro to do it's work.

I eventually went to "pro-shifted" 2nd and 3rd gears in my Saginaws to get clean shifts at 7500rpms. 3rd gear lugs only lasted a month or so before they needed attention, so i eventually faceplated 3rd. Here's a pic of a Saginaw mainshaft that has synchro'd 1st, "pro-shifted" 2nd, and faceplated 3rd. 4th still had a synchro, as i only raced it on the 1/8mi...

 

Ran one of these in a 62 Chev 1/2 ton behind a pretty stout 350" with a lot of cam. 3.75 rear gear. Beat the **** out it for four yeas before it gave up. Truck turned 14.54 seconds in the quarter so it was no slouch. I really can't complain about its longevity/durability considering the way I drove it.

 

Thx for all the input and tech I really do appriciate it. I've never been much of a drag racer except the stuff you do in high school lol. I've always liked the old skool late sixties trans am racing hell I wanted to build a 302 before I was talked out of it. Anyways, I'm using the 26 lb flywheel because I tought it would help driving in town and I heard heavy was better for a saginaw. I have a late 70's chevy 1 ton with a 4 speed sag and it has a 350 and a massive flywheel. I have a 16lb stock replacement and a 10,000 rpm 12lb hell I have a triple disc if lighter is better j/k. So I guess the way I'll drive it mostly will be hard shifting up and down so whatever I need to make it work budget minded is what I'll go with. How much fluid does one hold and how does the summit shifter do. And I am trying to build a light car, I've swapped the subframes intergenerationally from a 74 to a 76 so I hope I have a good start.

 

So is a lighter flywheel the ticket or stick with te heavy one?

 

The key to making the Saginaw live is to reduce the torque spikes wherever you can.

In this case, a lighter flywheel will store less energy.
Discs with a marcel and sprung hub soften things a little.
The RAM discs with a sprung hub feature poly injected springs that help a little more.
Less aggressive lining material helps as well, sintered iron is what i use.
I also use a hydraulic timer to control the final bit of engagement...
hydraulic clutch slip timer

 

I had a Saginaw like yours in my '57 Chevy behind a stout 327 and drove it like I stole it. I never hurt it.

 

What flywheel tires and ring and pinion did you use.

 

I used a 17lb 153T SFI rated steel flywheel, 275/60-15 M/T drag radials, and a 3.73 rear gear.