6ply leaf springs

ihave a65dart post car tubbed leaf springs moved in. the front spring hanger on the passenger side has about a half inch of spacers compared to the drivers side has any one heard of this sort of set up for drag racing there is 6 ply springs on my car that have to be replaced would a five ply work or should i keep the same system on the car this the way it was set up when i bought it ? thankyou