Reassembling 8-3/4 and have a leaf spring question...

[7E-Bodies]

So the rear differential is coming together nicely and is looking new, thanks in large part to a few in this forum and for Dr Diff. Before I completely assemble, I'm seeking some advice on the leaf springs. It's an original U code car, 64k miles, spent a long time sitting warehoused. A local suspension shop claims to do many old classics and has original specs for my spring arch measurements. One old guy on the phone even suggested adding a little arch for greater rake. Being a purist, I politely stated I wanted stock specs to which he agreed. Is there a way I could lay these out and get a measurement as to how far they've sagged (if any)? For reference, it has a 3.23 SG behind it's original (rebuilt) 727. Any and all advice appreciated.

Kevin

[7E-Bodies]

 Anyone? 

[anlauto]

If you want it the same a a factory spring, and ALL  factory springs are now 50 years old, I'm not sure what you would compare it to, because all the springs will sag over time 

[7E-Bodies]

@anlauto that's exactly my point. Looking to get the factory specs or anyone's gauge methods as to tell how good mine are, as well as to keep any local shop honest. I'd rather not pay to have them done, then find it's ass sagging or too high when I assemble a year from now.