ok. I guess I don't know what 400lb/in would be. 400 inch pounds is 33 ft lbs, so certainly that isn't what you mean. But I asked more than once for an explanation so I digress. :)
400lb/in means it takes 400 pounds to compress the spring 1 inch. That’s how the spring rate is measured. You can use it to calculate open pressure and loads at various lifts.
So a 350lb/in spring would need 350 pounds to compress the spring 1 inch.
