73-76 maybe 77 3/4 Ton Driveshaft

[HotRodPC]

Anyone have a driveshaft out of a 73-76 3/4 ton 2wd truck? It will need to be a small block truck with a Th350 so that it has a Th350 auto transmission.

I'm wanting to find a driveshaft for the set up. Or maybe at least some measurements and to know which U joints are in it. My Torque Converter has bit the dust in the C20. I'm thinking of putting a 700r4 in that truck. A driveshaft to a Th350 out of a square with a 9 in tailshaft should fit. But, I need it to fit the length of a 14B Full Floater, not a 12 or 10 bolt rear end, and I need to know if it will have the bigger 3/4 ton U joints so I don't have to use special conversion U joints and give up U joint strength by using a 1/2 ton driveshaft.

If anyone has one laying around and can gimme some measurements, or close enough to swap some parts, lemme know please. Thanks

 

[HotRodPC]

Noone with a 73-76 3/4 ton huh??? even for some measurements or let me know the cup size on the rear U-Joint?

 

[RetroC10Sport]

Rear section will be 37-7/32" based on a 1973-80 C20 with a TH350.

CHEVROLET 20 PICKUP 73-74 4x2; 131.5" WB, AT, TH350, rear section

CHEVROLET 20 PICKUP 73-74 4x2; 131.5" WB, MT, 3 spd, rear section

CHEVROLET 20 PICKUP 75-77 4x2; AT, TH350, rear section

CHEVROLET 20 PICKUP 75-77 4x2; MT, 3 spd, rear section

CHEVROLET 20 PICKUP 78-80 4x2; 131.5" WB, AT, TH350, rear section

CHEVROLET 20 PICKUP 78-80 4x2; 131.5" WB, MT, 3 spd, rear section

CHEVROLET 20 PICKUP 79-80 4x2; 131.5" WB, AT, TH400, rear section, 8-350 (5.7L)

CHEVROLET 20 PICKUP 80 4x2; 131.5" WB, AT, TH400, rear section, 6-292 (4.8L)

GMC 2500 PICKUP 73-74 4x2; 131.5" WB, AT, TH350, rear section

GMC 2500 PICKUP 73-74 4x2; 131.5" WB, MT, 3 spd, rear section

GMC 2500 PICKUP 75-77 4x2; AT, TH350, rear section

GMC 2500 PICKUP 75-77 4x2; MT, 3 spd, rear section

GMC 2500 PICKUP 78-80 4x2; 131.5" WB, AT, TH350, rear section

GMC 2500 PICKUP 78-80 4x2; 131.5" WB, MT, 3 spd, rear section

GMC 2500 PICKUP 79-80 4x2; 131.5" WB, AT, TH400, rear section, 8-350 (5.7L)

GMC 2500 PICKUP 80 4x2; 131.5" WB, AT, TH400, rear section, 6-292 (4.8L)

Nothing on the front about length...

CHEVROLET 10 PICKUP 78-80 4x2; 131.5" WB, AT, TH350, two-piece, front section

CHEVROLET 10 PICKUP 82 4x2; 131.5" WB, two-piece, front section, AT

CHEVROLET 10 PICKUP 85-86 4x2; 131.5" WB, two-piece, front section, AT, TH350

CHEVROLET 20 PICKUP 75-77 4x2; AT, TH350, front section

CHEVROLET 20 PICKUP 78-80 4x2; 131.5" WB, AT, TH350, front section

GMC 1500 PICKUP 78-80 4x2; 131.5" WB, AT, TH350, two-piece, front section

GMC 1500 PICKUP 82 4x2; 131.5" WB, two-piece, front section, AT

GMC 1500 PICKUP 85-86 4x2; 131.5" WB, two-piece, front section, AT, TH350

GMC 2500 PICKUP 78-80 4x2; 131.5" WB, AT, TH350, front section

 

[HotRodPC]

So the Th350 was used in C20's up through 80? That's good to know.

It would be nice to know the front length on the 73-80 too and be able to compare it to the 81- up so then I'd know if the carrier bearing splits the shafts at the same position for sure. I'd imagine it does. If not, I'll just add that cross section, so I can leave the OEM position there in case I go back to it. That's how I had my 62 and 64 set up, so I could swap in about any different motor and trans combo without having to RE Mod anything. It was all bolt in and swapped back in a few hours. Thanks for the info. That opens up a few more year models to look for the shaft in at PAP

 

[RetroC10Sport]

Let me see if I can cross reference a 700r4 front shaft.

 

[RetroC10Sport]

CHEVROLET 20 PICKUP 84 4x2; 131.5" WB, front section, AT, TH700, exc. 8-350

CHEVROLET 20 PICKUP 85-86 4x2; 131.5" WB, front section, AT, TH700

CHEVROLET 20 PICKUP 87 4x2; exc. Crew Cab; front section, AT, TH700

GMC 2500 PICKUP 84 4x2; 131.5" WB, front section, AT, TH700, exc. 8-350

GMC 2500 PICKUP 85-87 4x2; 131.5" WB, front section, AT, TH700

24.02"

CHEVROLET 10 PICKUP 83-84 4x2; 131.5" WB, two-piece, front section, AT

CHEVROLET 10 PICKUP 85-87 4x2; 131.5" WB, two-piece, front section, AT, TH700

CHEVROLET 20 PICKUP 83 4x2; 131.5" WB, front section, MT, AT, TH700

CHEVROLET 20 PICKUP 84 4x2; 131.5" WB, front section, AT, TH700, 8-350 (5.7L)

GMC 1500 PICKUP 83-84 4x2; 131.5" WB, two-piece, front section, AT

GMC 1500 PICKUP 85-87 4x2; 131.5" WB, two-piece, front section, AT, TH700

GMC 2500 PICKUP 83 4x2; 131.5" WB, front section, AT, TH700

GMC 2500 PICKUP 84 4x2; 131.5" WB, front section, AT, TH700, 8-350 (5.7L)

24.20"

 

[RetroC10Sport]

CHEVROLET 10 PICKUP 73-80 4x2; 117.5" WB, AT, TH400, front section

CHEVROLET 10 PICKUP 73-80 4x2; 131.5" WB, AT, TH400, front section

CHEVROLET 20 PICKUP 73-74 4x2; 131.5" WB, AT, TH400, front section

CHEVROLET 20 PICKUP 75-77 4x2; AT, TH400, front section

CHEVROLET 20 PICKUP 78-80 4x2; 131.5" WB, AT, TH400, front section

CHEVROLET 20 PICKUP 81 4x2; 131.5" WB, AT, front section

CHEVROLET 20 PICKUP 82 4x2; 131.5" WB, front section, AT

CHEVROLET 20 PICKUP 83 4x2; 131.5" WB, front section, MT, AT, TH400

CHEVROLET 20 PICKUP 84-86 4x2; 131.5" WB, front section, AT, TH400

CHEVROLET 20 PICKUP 87 4x2; exc. Crew Cab; front section, AT, TH400

CHEVROLET 30 PICKUP 80-81 4x2; 131.5" WB, front section, AT

CHEVROLET 30 PICKUP 82 4x2; 131.5" WB, front section, 8 cyl, AT

CHEVROLET 30 PICKUP 82 4x2; 135.5" WB, front section, 8 cyl, AT

CHEVROLET 30 PICKUP 82 4x2; 159.5" WB, front section, 8 cyl, AT

CHEVROLET 30 PICKUP 83-87 4x2; 131.5" WB, front section, AT

CHEVROLET 30 PICKUP 83-88 4x2; 135.5" WB, front section, AT

CHEVROLET 3500 PICKUP 89 4x2; 135.5" WB, front section, AT

GMC 1500 PICKUP 73-80 4x2; 117.5" WB, AT, TH400, front section

GMC 1500 PICKUP 73-80 4x2; 131.5" WB, AT, TH400, front section

GMC 2500 PICKUP 73-74 4x2; 131.5" WB, AT, TH400, front section

GMC 2500 PICKUP 75-77 4x2; AT, TH400, front section

GMC 2500 PICKUP 78-80 4x2; 131.5" WB, AT, TH400, front section

GMC 2500 PICKUP 81 4x2; 131.5" WB, AT, front section

GMC 2500 PICKUP 82 4x2; 131.5" WB, front section, AT

GMC 2500 PICKUP 83-87 4x2; 131.5" WB, front section, AT, TH400

GMC 3500 PICKUP 80-81 4x2; 131.5" WB, front section, AT

GMC 3500 PICKUP 82 4x2; 131.5" WB, front section, 8 cyl, AT

GMC 3500 PICKUP 82 4x2; 135.5" WB, front section, 8 cyl, AT

GMC 3500 PICKUP 82 4x2; 159.5" WB, front section, 8 cyl, AT

GMC 3500 PICKUP 83-87 4x2; 131.5" WB, front section, AT

GMC 3500 PICKUP 83-89 4x2; 135.5" WB, front section, AT

GM early '73 25-17/32x2-3/4".

GM late '73 up 25-1/32x3".

 

[RetroC10Sport]

CHEVROLET 20 PICKUP 81 4x2; 131.5" WB, AT, rear section

CHEVROLET 20 PICKUP 81 4x2; 131.5" WB, MT, rear section, 3 spd

CHEVROLET 20 PICKUP 82-83 4x2; 131.5" WB, rear section, exc. 8-454; AT

CHEVROLET 20 PICKUP 84 4x2; 131.5" WB, rear section, AT, TH400, exc. 8-454

CHEVROLET 20 PICKUP 84 4x2; 131.5" WB, rear section, AT, TH700, 6-250 (4.1L)

CHEVROLET 20 PICKUP 84-86 4x2; 131.5" WB, rear section, AT, TH700, 8-305 (5.0L)

CHEVROLET 20 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH400, 8-350 (5.7L)

CHEVROLET 20 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH400, 8-379 (6.2L, diesel)

CHEVROLET 20 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH700, 6-262 (4.3L)

CHEVROLET 20 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH700, 8-379 (6.2L, diesel), VIN (8th digit) "C"

CHEVROLET 20 PICKUP 87 4x2; exc. Crew Cab; rear section, AT, 6-262 (4.3L)

CHEVROLET 20 PICKUP 87 4x2; exc. Crew Cab; rear section, AT, 8-305 (5.0L), TH400

CHEVROLET 20 PICKUP 87 4x2; exc. Crew Cab; rear section, AT, 8-350 (5.7L)

CHEVROLET 20 PICKUP 87 4x2; exc. Crew Cab; rear section, AT, 8-379 (6.2L, diesel)

GMC 2500 PICKUP 81 4x2; 131.5" WB, AT, rear section

GMC 2500 PICKUP 81 4x2; 131.5" WB, MT, rear section, 3 spd

GMC 2500 PICKUP 82-83 4x2; 131.5" WB, rear section, exc. 8-454; AT

GMC 2500 PICKUP 84 4x2; 131.5" WB, rear section, AT, TH400, exc. 8-454

GMC 2500 PICKUP 84 4x2; 131.5" WB, rear section, AT, TH700, 6-250 (4.1L)

GMC 2500 PICKUP 84-86 4x2; 131.5" WB, rear section, AT, TH700, 8-305 (5.0L)

GMC 2500 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH400, 8-350 (5.7L)

GMC 2500 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH400, 8-379 (6.2L, diesel)

GMC 2500 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH700, 6-262 (4.3L)

GMC 2500 PICKUP 85-86 4x2; 131.5" WB, rear section, AT, TH700, 8-379 (6.2L, diesel), VIN (8th digit) "C"

GMC 2500 PICKUP 87 4x2; 131.5" WB, rear section, AT, 6-262 (4.3L)

GMC 2500 PICKUP 87 4x2; 131.5" WB, rear section, AT, 8-305 (5.0L), TH400

GMC 2500 PICKUP 87 4x2; 131.5" WB, rear section, AT, 8-350 (5.7L)

GMC 2500 PICKUP 87 4x2; 131.5" WB, rear section, AT, 8-379 (6.2L, diesel)

36.74"

 

[RetroC10Sport]

I don't know if any of this helps, it's an hour past my bedtime.

 

[cbrodine]

I have a 73 3/4ton w/ two piece driveshaft. It was behind a 4 speed though, Im swapping to a 700R4 also. I'm curious what I'll need(and from what) to mate the driveshaft to the 700R4...?

 

[HotRodPC]

I have a 73 3/4ton w/ two piece driveshaft. It was behind a 4 speed though, Im swapping to a 700R4 also. I'm curious what I'll need(and from what) to mate the driveshaft to the 700R4...?

So you're looking for the same thing I am. A driveshaft from a 3/4 ton since it'll be the 14 bolt full floater rear axle. Then an early model truck, some 77's had Th350 in the 3/4 ton and I've even heard of some 78's. We're looking for a 3/4 ton with a Th350 since it'll have the right spline count of 27 for the 700r4, and the intermediate shaft Th350 and 700r4 are only 1/4 in different in length, so hopefully that 1/4 inch is room to play in the shaft length and not have to have it modified.

 

[Stewzer55]

So if you're considering a 700R4 in the C20, does that mean you're considering pulling the Fo' Fiddy Fo?

 

[cbrodine]

HotRod....so do you have a part number for the piece we need? I'd like to start looking and need something to reference.....

Did someone say 'fo fiddy' fo'?

 

[HotRodPC]

So if you're considering a 700R4 in the C20, does that mean you're considering pulling the Fo' Fiddy Fo?

All depends. If I end up using the Fo Fiddy Fo in a TBI environment in my 85K10, or put it in the 91 Burb and TBI it, then yes I'll pull it, but NO for now, the plan is to keep the Fo Fiddy Fo, take out the 3.21 gear rear end, for a 4.10 rear end I have, and run the 700r4 behind the FiddyFo. If I break it, I'll disect it and make it better. I think the 4.10's will help it alot and I'm also going to keep the stock OEM tire size too. I don't know that a stock peanut port headed 454 really has enough torque and certainly not enough hp to tear up a mild properly built 700r4. But that's part of the purpose. Is to build it, tear it up and make it better all while getting some better mpg. The 4.10's and the 3.06 first gear will help the city mpg, and the OD will compensate the 4.10's. I want to build a 700r4 I can tow up to 3000lbs or so and still be able to use OD while doing so.

 

[HotRodPC]

HotRod....so do you have a part number for the piece we need? I'd like to start looking and need something to reference.....

Did someone say 'fo fiddy' fo'?

No, I do not. If anyone does, it would be RetroC10Sport. I think he posted the year models that we'd be looking for.

The closest I have is a single 1 pc shaft from 80 and 81 1/2 tons that had Th350 and Th350C and 12 bolt rear ends. So that means the smaller U Joints. And I don't know if the length would be correct even if I got the special U Joint for the rear end since I don't know if there is a length difference in the pinion on the 12 bolts and the 14b Full Floaters.

Close but no seegar !!! I was a Pull A Part last week and there was a 74ish 3/4 ton with Full Floater but the damn thing was a SM465 4 speed manual.