Need advise on rear springs for C10

[Fireball57]

First time posting but have found a wealth of information from this site. So here is my situation. My 72 C10 was converted many years ago to a 4wd long before I got it. It had 2" lift springs on the front and 2" blocks in the rear. I decided I wanted deeper rims and wider tires which is where my problem started. So I ordered some Procomp 4" front leaf springs for a 1973 dana 44 front axle and they fit perfectly. So I decided to order 6" rear springs to level the rear out. The newly ordered 6" rear springs measure 2 1/2" across and the stock leafs measure 2 1/4" wide on the rear. I have hammered, beat and pryed the last couple of days to get them installed with not much luck.

I have a 1972 c10 with a 12 bolt rearend and it looks like the shocks have been relocated due to the welds. I don't know what springs I should have ordered to fit properly. Any links for the correct springs would be helpful or just general advise. I could provide pics if that would help. Thanks!