If I recall correctly - valve springs, coil springs, leaf springs - are all qualified by spring rate.

There may be durability differences between the various metals used.

I recall also that back in the day when Super Stock springs were the go to spring - they were "bulldozed" when new. That means they were over compressed after they were built. This resulted in them taking the proper set (chamber). Sort of reverse "re-arcing".

I'm guessing since these are "Hecho en Mexico" - that's not being done now. So they take a set on your car.

I think the good ones used to be made in Canada.

Back to Kuality Kontrol at Ma Mopar' Performance Parts Group being out to lunch.

EDIT :

I typed in bulldozing springs in Google and it took me to Suspension Specialists - Tech Talk.

So I guess my memory isn't too bad after all.