3 to 4 speed trans swap

[Bonnewagon]

First, be aware that you need the correct tailhousing Saginaw to work with the A/G shifter set up. It has a flat side so the shifter can mount more forward. Keep your 3 speed shifter mounting plate, the 4 speed will need it too. That is the odd plate that bolts to the tail section and the midsection. Then find a Hurst shifter with rods for an A/G body and it will fit even with a bench seat.That is the purpose of that strange shifter mount, to clear the bench seat. If all you can find is an "F" body transmission and shifter with rods and mount, you can use them, but must use bucket seats as it will sit 6" rearward. Almost any Hurst shifter will work, but the installation kit is key as the shift rods and that mount are A/G body specific and are available new but expensive. Here is a pic of the correct shifter, rods and mount for our cars, except I used a 68' Firebird offset shifter arm to get the handle more centered .The floor hole is open where an "F" body shifter would need to be.

 

[oldtinsmith]

Bonnewagon,
Thanks for your input! Any input is a good thing. The G-body Hurst 4-speed shifter kit I got for the shifter has the exact same mounting plate that you have in your picture. The shifter itself is different than yours (very little offset for the handle and was made in CHINA! So much for Hurst!) I do have a shifter like the one in your picture also.
The trans was from a 1976 Camaro and I have mounted the new G-body shifter on it and it fits the factory hole perfectly. The shifter handle is exactly where the 3-speed was (with no slop!).
I must tell you that i really like the short throw of the Street Super shifter as well as the heavy duty, straight shifter rods! Talk about solid!!! BUT, it sits almost to the end of the tail housing and up about 2 inches (it was a perfect fit in the ChevyII for shifting).

Doug

 

[oldtinsmith]

kuruption 109,

The numbers on the Hurst shifter boxes are as follows: Competition/Plus shifter- 391 8794, and the Competition/Plus kit- 373 0017
I bought the shifter and kit about a year or so ago.

Doug

 

[Bonnewagon]

Doug, I liked that Supershifter also, but in my 77' TA it sat so high I needed a cut down handle to be comfortable. I ended up not using it and used the crummy stock shifter for now. It's an 82' ST-10 and the shifter mounts on the passenger side, not a good set up at all. I think I can use a universal Hurst mount but that has to wait. As for the Saginaw in our cars, almost any Hurst shifter will work as they are basically all the same guts. The only differences are the shifter forks that work the rods and the arm that sticks out and the handle bolts to. All the ones I have use the same forks. If you acquire several swap meet shifters you can change those parts around as I did. Kuruption109 if your new Saginaw has the rounded tailhousing, the proper forward mounted shifter won't fit. But you can swap the flat sided tailhousing off your 3 speed onto the 4 speed. The added gear is in the main case, and the tailhousings are the same. You wanted to see how they came apart anyway, right? Anyway, this is why I used the offset 68' Firebird arm, to get it all to fit the console.

 

[oldtinsmith]

kuruption109,

FYI......Some input shafts on the Saginaw 4-speeds had grooves on them. No groove: 1ST= 2.84, 2ND= 2.01, 3RD= 1.35, and 4TH= 1.00.......One groove: 1ST= 2.54, 2ND= 1.80, 3RD=1.44, and 4TH= 1.00.......Two grooves: 1ST= 3.11, 2ND=2.20, 3RD= 1.47, and 4TH= 1.00.......Three grooves: 1ST= 3.50, 2ND= 2.47, 3RD= 1.65, and 4TH= 1.00.
If you're not planning on keeping both transmissions and if they have a different groove count (one reason for keeping both) choose the one that has the best first gear ratio for your rear end gear.

Doug

 

[kuruption109]

kuruption109,

FYI......Some input shafts on the Saginaw 4-speeds had grooves on them. No groove: 1ST= 2.84, 2ND= 2.01, 3RD= 1.35, and 4TH= 1.00.......One groove: 1ST= 2.54, 2ND= 1.80, 3RD=1.44, and 4TH= 1.00.......Two grooves: 1ST= 3.11, 2ND=2.20, 3RD= 1.47, and 4TH= 1.00.......Three grooves: 1ST= 3.50, 2ND= 2.47, 3RD= 1.65, and 4TH= 1.00.
If you're not planning on keeping both transmissions and if they have a different groove count (one reason for keeping both) choose the one that has the best first gear ratio for your rear end gear.

Doug

from the pics can u tell what gears it have?

gettin cleaned up

quick primer job its just temp

 

[oldtinsmith]

No grooves, it should be a 2.84 first gear.

Doug

 

[kuruption109]

No grooves, it should be a 2.84 first gear.

Doug

hen u say no grooves what r u referring to?

 

[oldtinsmith]

The input shaft (that the clutch disc slides on) has no grooves ground into the splines (around the circumference)! Some transmissions have one groove, some two grooves, and some have three grooves.

Doug

 

[kuruption109]

The input shaft (that the clutch disc slides on) has no grooves ground into the splines (around the circumference)! Some transmissions have one groove, some two grooves, and some have three grooves.

Doug

o ok u talkin about the front piece lol (duh chris)