torsion bars and spring plates?

[NCbug]

Ok so i bought a set of 28 mm torsion bars from CIP1 . On the site it said 68-72 was 24-11/16 size ,mine being a 72 i took their word and bought them . Needless to say i take my old torsion out and find out this one is too small. So what can i do about this so i wont have to return them? Can i use spring plates from a different year bug or something? Or is the difference on the inside of the torsion tube. HELP