Help with Saginaw for a metric

[3dinter]

I am looking to go to a Saginaw and take out the automatic. I have no clue about what to look for, input spline #, output spline #,,gear ratio first and second, etc, etc. Any good articles, books websites. we run a semi banked 1/4 mile, currently putting out about 6000 rpm with a final of 6.45..i would like to stay around 6500 - 6800....."per rules" we have to stay with gm/gm..i have a 10 bolt 2.56 in the rear currently with the automatic, will change it when i put in the manual, what rear gear would be good also. The rpm's are an assumption based on what i think my stock motor can handle.

[DANNY]

Well heres what I see as an issue, the rear gears...

No matter what saginaw trans you run (unless you ran 1st) will work with that ratio.

Sounds like you want to be around ~6.50-6.83 final, with that you need to switch to a 4.10 rear and run the trans with no ring (grooves) on the input shaft which has a 1.68 2nd and will give you about a 6.88 final.

Then theres the 2 and 3 ring trans that has a 1.84 and 1.89 2nd and with a 3.73 rear gives you 6.86 and 7.05...

[fast_crew]

1.89 second, and 3.42 rear gives you 6.46 total. You have to look at the rings that go around the input shaft to identify, and hope that no one has changed the internals. The ratios are as mentioned above. And can be found on several sites, Racersguide.com had a list but there site is down.

[DANNY]

1.89 second, and 3.42 rear gives you 6.46 total. You have to look at the rings that go around the input shaft to identify, and hope that no one has changed the internals. The ratios are as mentioned above. And can be found on several sites, Racersguide.com had a list but there site is down.

Forgot about 3.42 been a while since I had a 10 bolt lol...

If rules/funds allow I would suggest at min a 9" rear of some sort they are out there and even have disk brakes stock. And if you can afford and maybe find one in good shape used a floater would be best not only the 9" center but its SAFER... That way you can run the trans in 1:1 and pick the right rear gear as well.

If you go with a 9" stock find someone to help set it up with metric mounts or send to someone that can they will also know pointers like tack welding the bearings to the axel lol thats important stuff lol... ;0

[3dinter]

different articles, different ratios....

# of grooves 1st 2nd 3rd 4th Notes:
0 2.85 2.02 1.35 1.00
1 2.56 1.81 1.37 1.00 Third gear on cluster has 25 teeth
1 2.56 1.81 1.44 1.00 Third gear on cluster has 21 teeth
2 3.11 2.20 1.47 1.00
3 3.50 2.48 1.65 1.00

GM Saginaw 2.54 1.50 1.00 --
GM Saginaw 2.84 1.68 1.00 --
GM Saginaw 3.11 2.20 1.47 1.00
GM Saginaw 2.85 2.02 1.35 1.00

Saginaw
M20 67 3915032 3.11 2.20 1.47 1.00 L6 engine
M20 68-69 3925656 3.11 2.20 1.47 1.00 L6 engine
M20 67 3915032 2.54 1.80 1.44 1.00 V8 engine
M20 68-69 3925656 2.54 1.80 1.44 1.00 V8 engine

Saginaw
M15 67 3858986 2.85 1.68 1.00 L6 engine
68-69 3925647 2.85 1.68 1.00 L6 engine
67 3858986 2.54 1.50 1.00 V8 engine
68-69 3925647 2.54 1.50 1.00 V8 engine

Saginaw 3-speed 1st 2nd 3rd
No Lines (grooves) 2.85 1.68 1.00
1 Line (groove ) 2.54 1.50 1.00
2 Lines (grooves) 3.11 1.84 1.00
3 Lines (grooves) 3.50 1.89 1.00
Others found but not with complete specs:
------------------ 2.54 1.88 1.00

Saginaw 4-speed 1st 2nd 3rd 4th
No lines (grooves) 2.84 2.01 1.35 1.00
1 Line (groove ) 2.54 1.80 1.44 1.00
2 Lines (grooves) 3.11 2.20 1.47 1.00
3 Lines (grooves) 3.50 2.47 1.65 1.00
Others found but not with complete specs:
------------------- 2.20 1.64 1.47 1.00