Rear Leaf Spring Perch Question

[TnBlkC230WZ]

I need to replace the leaf spring perches on my GM 12 bolt rear axle in a 71 Nova. I need to know what angle to install them at and what is the angle in relation to, yoke or cover plate? I've searched a while for this, but haven't found it. My drivetrain is a small block with a Muncie 4spd. I plan to change to a TKO or Richmond 5spd overdrive in the next 12 - 18 months if that impacts the angles. I'm installing Hotchkis rear springs in March and need to replace the perches before I do. The old ones are crushed and cracked. They were also installed with too much up angle.

A shop has advised me to install everything, set the pinion angle, then weld them, but I fear torquing the u-bolts down will distort the perches if they are not welded first. It also requires I drive to the shop unwelded. I also don't want to disassemble the rear again to paint the welded areas. Given Currie, Moser and others sell complete rears, there must be a proper angle to set them to before installing the rearend. There must be a correct installation procedure for this.

[TnBlkC230WZ]

I called Moser Engineering and ordered the spring perches from them. The said the perches are welded on at and angle 6 degrees down to the front and toed in 3 degrees. This is done in relationship to the yoke. This doesn't sound too hard.

The salesman on the phone sounded very knowldedge and even said I could call back when I'm actually welding them on. That's what I call customer service

[Norwoodx55]

Good to know they are so helpfull. Some companies consider that kind of info to be top secret.