it will be a mix of things, loosen the arb where it mounts to the shell and try re aligning the wheels to give better clearance and then tighten the bolts back up, also undoing the bumper and giving it a twist then tightening it up also helps with clearance a bit. Finally you probably have the revised h14 arb, the early 3dr h13 pulls the wheels further back giving a bit more clearance, check the casting number where the arb goes through the tca on the drivers side to confirm.