C20 TH350 to 3 on Tree??

[woodsrider250]

Hello, all knowing! Been a while since I've been on here

My TH350 needs rebuilt, and I found a 75 C10 with a 3/tree being parted out. I'd prefer the manual, but don't want a hole in the floor or floor shift at all for that matter. Is this swap direct? I'd get the column/pedals/linkage/etc all with it obviously, but the real question from doing some research is the floor hump. Did the 3/trees use a high hump floor? If so, this is out of the question and I'll just get my TH350 gone through. Also, trans lengths different? I could look myself, but this truck is fairly far away from me. Sorry if this has been answered on here before, but I couldn't find it. THANKS!

 

[Georgeb]

your low hump floor will work fine.

 

[woodsrider250]

Sweet! Thanks.

Any idea on the length? I'm going to measure mine and ask the guy to compare. If the donor was a 3/4 LB I'd just take the shaft too.

 

[Georgeb]

not sure on the length.

 

[DoubleDingo]

As mentioned the low hump is sufficient. Don't forget to grab the pedals, bellhousing, steering column, linkage, driveline, basically anything that goes with the manual transmission grab it from the donor truck. I have a 3 on the tree and I don't mind it at all. You won't be slamming through the gears, and you need to make sure the column is adjusted properly so shifting is smooth, but I would get the manual. Heck check the gearing of the rear axle too, it may be a better ratio than what you currently have.

 

[woodsrider250]

Thanks...yes would get everything including flywheel.

It's a C10, and mines a 20 with 14b/8lug rear.

 

[woodsrider250]

So I picked this thing up. Research found that the 3sp is the same length as a 6" tail TH350 (my truck is of course 9"). Good news is the donor truck was also a longbed so I just got the shaft and everything. Seller is a member on here and found that there is a conversion u-joint to adapt the smaller/longer front shaft to my existing 3/4 setup.

 

[DoubleDingo]

If you got the shaft from that truck it should be a direct bolt in unless the carrier bearing is different. I think the ujoints are the same, but I may be wrong.

 

[DoubleDingo]

Before converting anything on the driveshaft, get it all installed and see if the shaft bolts in. I bet it does.

 

[woodsrider250]

Yeah, they might just go together nicely right at the slip joint without anything special.

 

[DoubleDingo]

I agree. Both trucks are long bed, and the shaft from the parted-out-truck was made for the 3-speed, so once you get the 3-speed in your truck the measurements will match and the shaft will slip in the back of the tranny. Unless you have the HD-3-speed with the bolted in yoke. Even then the length from the tranny yoke and the carrier bearing should be the same, and for sure from the carrier bearing to the axle.

 

[Keith Seymore]

The only other thing you need to be aware of is that 3 speed manual trans is a Saginaw trans, and is a very light duty transmission (like a passenger car trans).

They used it behind 6 cylinders in Camaros, too, in addition to 6's and small V8s in pickup trucks.

I would plan on not being too rough with it.

K

 

[woodsrider250]

Yeah, not too worried about it. A 4.3 V6 makes more power than this engine....LOL. The last time I ran one was in a Modified Stock Car, and they did OK.

 

[Keith Seymore]

Yeah, not too worried about it. A 4.3 V6 makes more power than this engine....LOL. The last time I ran one was in a Modified Stock Car, and they did OK.

I've never hurt one either (street use) but I tend to be pretty easy on equipment.

K