Which leaf springs to use?

Are you talking about new or used springs? If you bought a set of used springs from a race car and they are bent you can hardly blame the springs. If you bought new springs that were bent you should have exchanged them.
your missing the point ,I used to run 002-003 springs on a hemi belvedere , it hit them hard , did not bend one ever , but wore them out after a few yrs , the mexican springs wont take that now , unless they`ve changed . Your street car will not hit them like a full blown high h.p. drag car will ...
The bent springs I`m refering to came off of a well known drag racers 68 , 383 barracuda , ''stocker'' , of a few yrs back ....
couldnt tell they were bent if laying in the floor , on the car it showed up immediately.
The guy I bought them off of knew they were bent , but he is/was pretty well known for stuff like that ...I should have known better !!