Putting the Cuda back on the road

[HP2]

Moving the springs inboard does impact the rate, but not significantly. IIRC I believe it changes it about 10# per inch moved, or, not enough to really notice.

The 3/4" hanger/shackle change coupled with a B body housing is the easy recipe for additional clearance. Going this route with a 8.75 would allow you to retain your rebuilt third member, but you would not be able to  transfer your E body axles to it.  I don'think you said where the tightest clearance is on your set up but if its on the spring side, the spring relocate kit would  increase that space. Depending on the housing you use, it also could increase space on the fender side, but  you rim offset is also a factor in that.

[RUNCHARGER]

More bite to be gained by extra tire width I am sure.