changing rear axle

[JW76]

I have a 1969 12 bolt axle that I want to swap into my 1986 truck. The leaf spring perches are 45 inches apart just like the current 86 axle but the perches themselves are a half inch narrower than the 86 ones. Do I need to cut them off and put the wider ones on. In addition the shock mounts are in the wrong location. How should I go about this swap and what is the proper procedure for measuring the locations of the new perches and shock mounts and then welding them on? Thanks for any help.

[JW76]

Can you weld the wider perches on top of the old ones and center them. Will this work or will they be in the wrong location? In addition what method of measuring is accurate for locating the perches since the center section is off center and the differential cover bumps out so you can't measure straight across. Thanks

[Tx Firefighter]

If it was me, I'd just run it. The difference of 1/2 inch narrower pads isn't too big of a deal as long as they are indeed the proper distance apart. Just make sure they locate onto the spring pins and cinch the u-bolts down tight.

[JW76]

I'll give it a try. Thanks for your help.