I've used over half a dozen RB hinges on Mustangs and sometimes you have to shim them and sometimes you don't... all depends on the car. Worst one we had did need about 1/4" of shim/spacer on the top for each side to level the hinge out.
Build tolerance in the 60's wasn't what it is now.... 1/4" long here.... 1/4" short here.... And then there are these chinese American Muscle cars that must be a completely different shape... everytime I get a replacement part from China I swear it was made to go on a different vehicle!
