Moving the IRS rearward

[Butlers24rth]

I did mine last year. I moved it 1 1/4 inches back.
Not too bad
I can outline
Remove IRS, have drive shaft xtnded 1 1/4
Shock mounts: Welded and additional 2 inch pc of steel to the back of the mount. drilled new holes 1 1/4 inches back. I also added gussets to the top to strengthen it.
Front tray mount: made a 1 1/4 X 2" solid pc of alum as a spacer bar, bought longer grade 8 bolts
Cut loose the rear Tracking/ adjustment bars from the frame. I simply seperated the angle from the frame keeping the Hime joint mounts all together then when I re installed the IRS I welded it back to the frame 1 1/4 back
The most work was the upper mount to the top of the diff. I used a pc of 2 x 4 x 1/4 tube on end and 4 in axis front to back, had to cut a contured pc to fit the frame crossover bar on the other end of the tube I cleaned up and re used the plate that attaches to the top of the diff. I gusseted this as well. You have to make/ buy new bolts to thread into the top of the diff as the old ones are too long to get between the frame and the mounting plate. Check before you weld.
I did all of the welding in the car using pcs of sheet metal as heat barrier.I am very happy with it and I have not broken it, at least not yet!!
Good luck, Scott

[lal Naja]

Originally Posted by Butlers24rth

I did mine last year. I moved it 1 1/4 inches back.
Not too bad
I can outline
Remove IRS, have drive shaft xtnded 1 1/4
Shock mounts: Welded and additional 2 inch pc of steel to the back of the mount. drilled new holes 1 1/4 inches back. I also added gussets to the top to strengthen it.
Front tray mount: made a 1 1/4 X 2" solid pc of alum as a spacer bar, bought longer grade 8 bolts
Cut loose the rear Tracking/ adjustment bars from the frame. I simply seperated the angle from the frame keeping the Hime joint mounts all together then when I re installed the IRS I welded it back to the frame 1 1/4 back
The most work was the upper mount to the top of the diff. I used a pc of 2 x 4 x 1/4 tube on end and 4 in axis front to back, had to cut a contured pc to fit the frame crossover bar on the other end of the tube I cleaned up and re used the plate that attaches to the top of the diff. I gusseted this as well. You have to make/ buy new bolts to thread into the top of the diff as the old ones are too long to get between the frame and the mounting plate. Check before you weld.
I did all of the welding in the car using pcs of sheet metal as heat barrier.I am very happy with it and I have not broken it, at least not yet!!
Good luck, Scott

Thanks Scott.

I've just finished moving mine back 3/4". I guess I could have gone more but felt that 3/4 was all I needed. If I had your post to read before I started, perhaps I would have gone the extra 1/2" too. Ah well!

With regard to your drive-shaft. How far into the transmission tail does yours go?

As there is no sliding of the spline in the transmission because of the rigidly fixed IRS, I'm making my drive shaft longer with only 1/4" of clearance in length. That's long enough to slide it all the way into into the transmission and bolt it to the diff flange. Previously, my drive-shaft was 1 1/8" shorter and I think that was far too short.

Arthur