j20owner wrote:...
Oh, and I need some pointers on the 14 bolt install from some of you who've done something similar. The wag has already had a shackle flip performed in the rear, but the front mounts were not modified. I would rather modify spring mounts on the frame than try to get the perches off this 14 bolt. I think my math puts the spring hangers in their standard configuration at 44" center to center and the 14 bolt has the perches at 42" center to center. Right now I'm thinking it will end up with 63 inch chevy springs in the rear, so it might just get clean rear frame rails in the end anyways. Also, I'll need to match the 'lift' in the front, which is a SOA on stock 79 J20 front springs.
Perches are easy to remove.
Get a zip wheel for your grinder and a big hammer and you will have them off in about 5-7 min per perch with minimal damage to either.
You are probably going to reposition them anyway for a proper pinion angle, either that or run shims to correct the angle.
Shoot me some pic's of what was done to the rear.
I deal with this and questions like this quite frequently.
If you do the standard rear shackle flip (either kit or home brew) you will match the front height pretty spot on.
If you move hangers under the frame you will gain a bit more height in the rear, nothing unworkable at all.
There are also folks that have used Dodge and Ford hangers upside down (I think they install them upside down?).
63" springs will push your axle back 5-6" if you mimic the location of the front most rear hanger.
If you go with a kit (that's what they do, mimic that placement, just lower for proper pinion angle) you are moving wheel wells.
If you go hangers under frame you get to decide where you want the axle to wind up.