Need 10 More Inches of Driveshaft

[stickshift_or_walk]

So I've changed from the I6/3spd to V8/4spd, and that's pretty well buttoned up. But it would be nice to get the new setup connected to the rear wheels, and that's where I need some advice.

All the steps that got me to this point are covered in this thread:

http://67-72chevytrucks.com/vboard/s....php3?t=110405

But here I am with two problems:

1) The old engine/tranny combination put the rear of the transmission 10" farther back than the new one, and

2) The slip joint in the rear of the 3spd won't work on the SM465 4spd since it has a solid yoke on the back to accept a u-joint, with no slip.

The original driveshaft has the small carrier bearing forward of the center crossmember (the one the trailing arms mount to). The front section actually passes through the crossmember, where a center u-joint connects it to the rear driveshaft. If I just fit up a front section that will bolt to the yoke on the rear of the SM465, I won't have any slip in the shaft and it's bound to need some, even though folks tell me it doesn't need much because the trailing arms don't compress the shaft like leaf springs do. The other problem would be fitting a longer shaft, since I'm having trouble locating longer lengths of that size tubing, and my local shops can only change yokes, because they don't have a way to balance a whole new shaft.

I do have hope because my '72 C20 has a different setup. It has a much larger carrier bearing mounted behind the crossmember, with a slip joint on the rear section of driveshaft. That way, when I made the automatic-to-manual swap in that one (also SM465), I just got a longer front shaft made and mated it to the rear slip-joint. I believe the front section ends with spines that mate through the carrier bearing and into the female end of the rear section.

So one solution would be to find a whole setup like the one in my C20 and refit it to the C10, with a longer front shaft made up to fit. The tricky part of this is the different bracket I'll need to mount the larger carrier bearing to the rear of the crossmember, and removing the riveted bracket that held the smaller carrier bearing in front of the crossmember.

Does anyone know a better way to do this, or know something I'm missing?

Thanks...SSOW

[Tx Firefighter]

stickshift, I sent you a PM concerning this solution.

[66nova383]

On my 69 swb it had a longer front shaft with a carrier bearing set up mounted to the back side of the crossmember kinda hokie.I want to switch to a 1 piece shaft,but when I lower the rear 4 inches will I have to cut the hole in the crossmember bigger so drive shaft don't hit during suspension travel.Anybody have any info on this? I have a t400 does anyone know what kind of car I could steal a driveline out of that would fit? thanks alot for any help

[jlmtrout]

I converted the two piece drive shaft to a one piece by taking the length measurements to TruckPro and had them make one for me. I did have to cut out the bottom of the crossmember, but by doing this I eliminated one u-joint and that pesky carrier bearing. Good luck and keep on truckin'.........Jerry


P.S. the cost was under $200

[ChevLoRay]

Boy, did I get a good deal....back in '73. I traded a '55 210 2-dr sedan straight across for a '56 Short step 3100 series pick up. The truck had been converted from 3 ona tree to an SM 420 4-speed. The previous owner didn't have the funds to have a drive shaft built. My (ex) father-in-law worked at a truck machine shop. I took my old drive shaft to them, and they installed a slip yoke and furnished 2 new u-joints, and balanced it all for $41.70. I had bought a yoke for the tranny, at a truck salvage yard, for $5. My ex-wife's uncle gave me the collar for the tranny to hold the shifter in place. I ended up with a total investment in the truck, of $201.70. Oh, it was straight and rust-free, too. Drove it for a couple of months, then swapped it for a '66 Chevelle SS 396, which I then traded for a beautiful '65 Ford SWB Custom Cab, that was running a 428 and a Hurst-shifted 3-speed.

Now, you say he should be able to get the driveshaft re-done for about $200. 31 years sure makes a difference, don't it?

[XXL]

Oh, how often I've heard this in my life

[Tx Firefighter]

Originally Posted by 66nova383

On my 69 swb it had a longer front shaft with a carrier bearing set up mounted to the back side of the crossmember kinda hokie.I want to switch to a 1 piece shaft,but when I lower the rear 4 inches will I have to cut the hole in the crossmember bigger so drive shaft don't hit during suspension travel.Anybody have any info on this? I have a t400 does anyone know what kind of car I could steal a driveline out of that would fit? thanks alot for any help

Dude, I've owned a bunch of these short bed trucks. Everyone has been lowered either 4 or 6 inches in the rear. With a 1 piece driveshaft, I've never had to enlarge the crossmember hole.

For my 70, I had the driveshaft built Monday. 57 inches center to center 1 piece with Turbo 400 yoke. My truck is lowered 6 inches in the rear. It's nowhere near rubbing on the crossmember.

[XXL]

Originally Posted by 66nova383

I want to switch to a 1 piece shaft,but when I lower the rear 4 inches will I have to cut the hole in the crossmember bigger so drive shaft don't hit during suspension travel.Anybody have any info on this?

As Tx Firefighter says... ye isn't going to rub

Here's my truck-- no rub.

[Tx Firefighter]

XXL, where have you been for the last year?

I was following your truck progress and then you quit posting....

[PICKMUP]

This is a LWB truck???
How about a complete driveshaft/carrier/mount out of a LWB, 1/2T that came from the factory with a 350 & SM465. That should make everything correct without any cutting/lengthing/etc.
If you are working with a SWB or want a one-piece driveshaft, please disregard this. I was getting a little confused with all of the other info being traded about.

[stickshift_or_walk]

Thanks PICKMUP, you're right on.

Yep, mine is a LWB 2WD, and we stray off the pavement too much (fishing, mostly) to drive a lowered truck. I'm also hesitant to cut that crossmember, since we won't be babying the truck.

I think you're on the right track, but I haven't been able to locate an original SB V8, SM420/465, LWB truck to study, much less to pick parts off of. If anyone can post a pick of this setup, I'd like to see it.

I took some pics of the setup on my '72 and plan to head out Tuesday looking for a match. Most of the driveshafts I've seen so far are stacked in the back of a derelict pickup in the salvage yard. Most folks around here just scratch their heads and wonder why I'd go to this much trouble for that old 4spd, when I could just go with an auto.

No use in trying to explain it...just call me SSOW...

[PICKMUP]

I have that complete package: 70 Chev, 1/2T, SM465 and it is still all together from trans to diff///in the truck.

[stickshift_or_walk]

PICKMUP -

Do you have any pics of that driveline? I'm particularly interested in what's in front of and behind that center crossmember.

Thanks...SSOW