doggonn

i have put a 425 in my 1965 cutlass also 355 posi and a 350 turbo trans my question is will the rubber filled driveshaft in the back u joint area hold up . im thinkinking it wont . so do i need a new tube or can the old one be welded solid advice needed thanks

70sgeek

budget permitting, I'd vote for a new solid driveshaft - you might save some cash on having one built locally if you have a driveline shop in your area, vs. buying one mail-order from an online vendor.

I had a completely new HD steel shaft built that way a few years back and paid about $300 out the door - included yoke and Spicer U-joints.

droldsmorland

No, the 2 a two-piece shaft cant be welded to make a solid shaft.

The OEM shaft may hold up if you don't do burnouts, have slicks, and keep max torque numbers at or under the stock application....for a 330.

Harsh shifting automatics(only ones to have IMO) will torque the tube out of phase. I know this first hand.
As the rubber ages, it will get brittle and eventually twist out-of-phase with abuse. Haven't heard of one completely failing but bet it's been done.

The 2 piece was designed for automatics. Less driveline harmonics transferred to you = the signature Olds cut above ride. A stick car would have a solid shaft.

A new solid thin-wall steel shaft is about ~$300-400. A new all-aluminum shaft is ~$650, (cats azz). New is better as you know it hasn't been abused(yet) and it's balanced.

Dennys Driveshafts has everything including instructions on how to properly measure and determine U-Joint series(size). He whittled me a very nice aluminum shaft.

https://www.dennysdriveshaft.com/

OLDSter Ralph

I wouldn't trust a 50 year old 2 piece (rubber bonded) drive shaft. I have heard people mention that the 2 piece drive shafts "like to hand grenade", but I never experienced it "back in the day". I never had a problem with a '68 Hurst/Olds or my '70 W-30. Both cars ran an "improved" TH400. The H/O had 4.33 gears, 7" M&H slicks at 10 PSI and the W-30 ran 10.00 X 15 M&H slicks at 8 PSI. The W-30 would chirp the slicks at 70 MPH when shifting into high gear.
......Just my two cents worth.

oldcutlass

I'd look into a replacement to a one piece down the road if your current 2 piece is still in good shape.

doggonn

thanks for the feedback i will be going solid and new

Loaded68W34

Another place to look is PST. They are currently building a new 4" aluminum shaft for my vista.
https://pstds.com/