So I finally did the 4l80e conversion. I took it out for a run and the trip lasted no longer than 20 minutes. The driveshaft or the yoke went out at about 80 mph. Do you think the driveshaft broke the slip yoke or the slip yoke broke the driveshaft? The slip yoke is still in the trans but with one of the ears broke off. The driveshaft is torn apart and missing the end. The slip yoke was a GM 3R (i think 1330, the company i ordered it from was sopposed to send me a 1350). As you know the GMT900's came with 1350's, so i had a conversion/bastard u joint up front 1330 yoke to 1350 driveshaft.

I would appreciate your thoughts on this as i need another driveshaft. If it was the yoke that took the driveshaft out i'll just buy another stock 5" driveshaft. If it was the driveshaft that broke the yoke i'll get a custom hp driveshaft from Inland Empire Driveline. I'm guessing I have around 500rwhp and my truck weighs around 5100lbs. Should I just go 1410's

At least I'm happy with the 0-60 times. I had both of my bbrothers in the truck extra 400lbs. One of them clocked it. I had quite a bit of wheel spin then I let off of the throttle and still got a 6.1 0-60.

 

Your problem is here^^^

Where did the shaft come from?

 

Any vibration? Who did the shortening of the drive shaft?

 

the shaft was the original.

 

there seemed to be a small amount. the driveshaft wasn't shortened. What is your driveshaft from? is it steel? what size? how do you like it?

 

Oh ok, I was under the impession you had a custom shaft made and then it broke. The factory shaft is junk for the kind of power your making and would have died eventually even with a good u-joint and slip yoke. I am running a 5" Alum shaft by Driveshaft specialist and couldn't be more happy. The 1350 joints should be plenty though.

 

How much did that run you? How much power you making? What thickness

 

Shaft, yoke, spicer joints, balanced and shipped was around $600 iirc. It was in my hands 3 or 4 days after I called in the order and it was the biggest diameter and wall thickness they offer. I'm building from the rear forward so only making stock power so far, but was told it would handle anything I can throw at it.

Here's the thread with pics comparing it to the factory shaft:
https://www.performancetrucks.net/fo...d.php?t=480931