Turbo 350 Information and Facts

[Sherrow74]

th350 replacement

I am going to replace my turbo 350 in my 1974 k10 soon and I was wondering if I could find any turbo 350 and use my current parts to mate it to my transfer case (np203) or do I have to find a 4x4 specific transmission. Would the output shafts interchange?

 

[HotRodPC]

You will need the correct output shaft to mate to any transfer case. If you're saying find any Th350 case, and use all your parts including the output shaft out of your current transmission, then yes you can do that. There are 3 different output shaft lengths for 2 wheel drive models and none of them will be a direct bolt in for your Transfer case and adapter due to the output shaft lengths.

 

[MikeB]

I just want to confirm that TH350 and TH350C cooling line ports are in the same place.

Thanks.

 

[MadOgre]

I have used the same lines from a th350 to a 700r4 to a th400.

 

[HotRodPC]

I just want to confirm that TH350 and TH350C cooling line ports are in the same place.

Thanks.

Yes, EVERYTHING is the same with exception of the input shaft, pump, torque converter and the C has the plug in for the Lock Up Converter.

 

[MikeB]

Thanks!

 

[TIC]

the info here is great, but for one thing, could somebody please tell me what the finished lengh is of the output shaft wether from the kit or cut down from a car tranny. im doing a swap from 700r to 350. i got a 350 out of a 75 4wd and a 350c out of a 84 pontiac. i've guted both trannys i butted both bell houseings to gether don't see any differance at all. was gonna use the 350 but after compairing the guts the 350c seems to be built much stronger internally. like the band is twice as wide as the 350. also what would happen if i hooked the lockup wires from the 700r to the 350c? i know the plugs are diferant. im talking useing the 350c plug and spliceing the wires.

 

[TIC]

the info here is great, but for one thing, could somebody please tell me what the finished lengh is of the output shaft wether from the kit or cut down from a car tranny. im doing a swap from 700r to 350. i got a 350 out of a 75 4wd and a 350c out of a 84 pontiac. i've guted both trannys i butted both bell houseings to gether don't see any differance at all. was gonna use the 350 but after compairing the guts the 350c seems to be built much stronger internally. like the band is twice as wide as the 350. also what would happen if i hooked the lockup wires from the 700r to the 350c? i know the plugs are diferant. im talking useing the 350c plug and spliceing the wires.

forget everything above its all wrong. i did the comparisons several months ago, i was just looking at the bolt patern, i just went out and did it again. the 4wd case is much thicker at the bellhouseing. and the guts a lot diferant behind the pump, the 350c has got a much wider heavy duty band, the 350 has much larger cluch pack. so i'm definetly going with the 350. but i still need to know the finished lengh of the output shaft, so i can cut this car shaft to the right size, you can buy just the spacer for around a 100 insted of the whole kit with the shaft and other stuff i don't need for around 200.

 

[crazy4offroad]

What size output and spline count do you need? What tcase? I'm sure someone has a spare. I think I have a stock TH350 4x4 output somewhere.

 

[TIC]

its a 27 spline, the problem is the 350 case is shorter than the 700r case so you have to use a spacer, the shaft can only be obtained by buying a spacer kit wich has the right lengh shaft or cutting down one from a car tranny. i have one to cut down, but i need to know how long to make it.

 

[crazy4offroad]

OK so you have a 700R4 shaft you're cutting down, I thought it was the other way around.

 

[TIC]

OK so you have a 700R4 shaft you're cutting down, I thought it was the other way around.

no i have two 350 trannys one from a 4wd and one from a car. im cutting the car tranny out put shaft down to use in the 4wd tranny to make up the diferance in lengh of the longer 700r case.

 

[TIC]

ok i just found installation instrucktions on pdf for the spacer kit, without the shaft. it say's to get a output shaft from a car tranny with a 6" tail piece, witch is what i have. it says to measure 31/4" from the center of the speedo gear clip hole. and cut off 13/8" . does that sound right to you guys that have done it?

 

[73CobraCAT]

So after reading through this it seems like its not worth it to have a tailshaft swapped at least on a th350. I recently got a 454 and built tci 350 out of a 2wd which has a 9in shaft and was going to put it in my 73 3/4 ton 4x4 suburban. If i took the tailshaft out of my 6in which is in the truck now and took that and the tci to a shop to have it swapped, what would the typical cost be?

 

[HotRodPC]

So after reading through this it seems like its not worth it to have a tailshaft swapped at least on a th350. I recently got a 454 and built tci 350 out of a 2wd which has a 9in shaft and was going to put it in my 73 3/4 ton 4x4 suburban. If i took the tailshaft out of my 6in which is in the truck now and took that and the tci to a shop to have it swapped, what would the typical cost be?

I'd expect $150 to $200 since it's not a full rebuild and no need to pull the drums, valve body or pump apart. But, a 6in output shaft isn't going to work for a 4x4. The output shaft will depend on which transfer case you're going to run.