I've got a set of variable rate rear springs for my 68 cutlass s.
buy don't know if the tight spiral goes up or down. Maybe it doesn't make a difference. Any help would be appreciated.

 

The tighter coils go down.

 

Neither the spring nor the car care which end is up. The response of the springs will be the same either way. Since the end coils are the same at either end, fitment into the spring pockets is not affected.

 

On variable rate springs (overload not stock, designed for trailer towing) that I have used, they have tighter spaced windings at one end and more spacing at the other. I put them in upside down intially, and the car had more bounce in it, especially when I put the trailer on the back. (1971 Cutlass)

 

Sorry, but the "butt force gauge" is about as accurate as the butt dyno. If you put these springs in a real force/deflection tester, you'll get the same curve of force vs. displacement with the tight coils oriented either way.

 

fixed