Suspension
I will answer your suspension question:
Yes you can get shorter springs if needed, with the car jacked up and no preload your springs should be 8" in length. I have never seen a Unique that required 6" or 7" springs on the rear. Generally a 427 body with coilovers takes a 8" spring rated at 350#, in my opinion this works the best. I think from there it is personal choice where you go, I think I would go toward 400# springs before going down to 300# which are light. The spring rate is scribed on the flat of the the spring, top or bottom. Dont try to adjust each side the same, wont work as one side will take more pre-load than the other to get the rear ride height equal as the tire sits in the tire well.
If you do have 10" springs on the rear get with Unique to swap them out, they are too long for the rear.
Rick
427 S/C , 427 Side-oiler, 4 Speed Close Ratio Top Loader, 3:73 Gear
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