Going from 8.75 to Dana 60, BB 4-speed deal. New rear will also be narrower (mini-tubbing too).

As long as I'm upgrading, was thinking about going to 1350 u-joints front and rear.

So I will need a new tranny yoke, the pinion yoke will be new anyway.

Now, the driveshaft. It will also need the bigger yokes at each end.
If I keep my current driveshaft, it will need to be shortened 1.125 for the new Dana,
but is the tube going to be strong enough ? How thick wall thickness are OE driveshafts ?
Is the OE tube not really the weak link ?
No slicks and no 8000 rpm clutch dumps.

I kept having the local driveshaft shop "fix" mine.

In the end it was cheaper to just order an all new Strange shaft with 1350 joints, new yoke, etc. from Dr. Diff.

No problems since!

Just use the measurement guide on Doctordiff's site and get a new Strange driveshaft. I don't think they make a weld yoke for a 1350 joint in a small tube like the factory size. You cant beat the deal on the one you get from Cass

Gus

Sound advice.
They really aren't that expensive , and if you order the shaft and yoke from Strange , then you don't have to send the yoke in to balance the shaft.
One stop shopping and a quality piece ?
I did the " local shop modify my shaft " deal years ago and it didn't end well.
I would have been way ahead , dollar wise , to simply have a new one made................which I had to do anyway , and replace the transmission case that broke when the driveshaft failed.
Luckily , it happened at about the 150 foot mark , before the car really started making steam.
But we were like the third set of cars down track that morning , and oiling the right lane delayed the program for about 45 minutes.
So we were not going to win any popularity contests in the pits that day.
Lesson learned.

Tubtar, what failed in the driveshaft ?

When I did mine, I went with a 3” tube with 1350 joints, ordered from Cass. It arrives ready to drop in.....no fuss.

I went with a 4 inch aluminum for strength and weight loss. Your power levels might vary

3" steel is a minimum. Depending on the length, they may want to go to 3 1/2". Especially with a manual trans.

Local shops are sort of okay for street rods and drivers, but none of the local places I have can spin them fast enough to get the balance right. And they also have trouble reading a dial indicator. Guys are used to building stuff for dump trucks, not race cars the go 8000RPM.

After a while, I just stopped trying to get it right from those guys.

Considering what usually happens when a shaft fails, I would not cheap out in this area.

Another vote for Doc Diff. You wont find better service in my opinion and you'll have solid part from Strange Eng. As stated, just follow the measurements exactly from his website and be done with it.

Exactly. I'm going to order another Strange driveshaft from Doctor Diff as soon as I get the 9 inch under the Duster. There is a local shop that says they can do race car driveshafts but they wanted more money than Strange charges. I have 100% confidence in the Strange driveshaft.

this ! ^^^^^ !

a good buddy of mine whines and bawls about a minute vibration in his chevy, but insists on having the truck shop build a driveshaft. with an overdrive transmission, the shaft needs to be balanced at a higher RPM than most think.

Our local shop is about double the cost of Dr. Diff and quality isn't as good. Not to mention the one shop has a nasty attitute. I try my best to keep my dollars local but on this case it was not worth the grief.

I kind of got the run around from strange on the phone when I asked about a driveshaft, seemed to more or less be be avoiding giving me any kind of solid answer. I probably should have just ordered through Cass because everything else from him has been great, just didn't think about it when I got the driveshaft made. I had a Local shop make it and I have been pleased.

It was a stock shaft I had shortened.
On street tires............it spun hard to 150 feet , then hooked and twisted the shaft in half...............about 18 " in front of the pinion yoke.
It had a fair amount of street miles , but first trip to the track , it had enough.
It came from a big block / four speed car ( 1966 Cyclone ) and now had a fairly tame motor and an automatic that was foot braked.

A few things to consider.

Yes torsional strength but more often overlooked is critical speed.

If you're getting new 1350 yokes I would upgrade the tube to a larger diameter as well. Now you've increased both torsional strength and critical speed.