rear end swap?

[chevytroy]

i have a 1951 chevy 1/2 ton. Ive picked up scott dansforth crossmember to use in the 51 frame. I also just picked up a 1999 gmc envoy 4x4 rear diff w/disc brakes. I installed the 1996 s10 leafs to it and now im alittle puzzled.
I know the pinion angle between 3-5 degrees. but do i re-use the stock mounts for the leaf from the s10? does some one make a kit. At this point Idont know if the stock mounts from the s10 will work cause the two frames have different angles. if anyone has pics or some advice it would help me very much.....