You need to be a little more specific as to how it is angled. Side to side? Top in? Bottom in? One side higher than the other?
One side higher than the other you have to loosen the bracket to tailpanel bolts and adjust, may have to open the holes some.
Side to side same thing, just shift it either way. Opening holes some may be required too. Most repro stuff, bumper, tail panel, brackets, ect will need some "tweaking".
With my 68 the repro rear bumper was angled in at the top, it was touching the body. I had to stack some stainless steel washers between the TOP of the bumper bracket and under the bumper and then put the bolts through those washers to hold them in place. I bought stainless so they won't rust.
The blue painters masking tape is great for stuff like this. Put it on the painted corners and areas of the body the bumper may hit. You can do a few layers if you want. Now if the bumper does tap the body while you're lining it up and installing it you've greatly decreased the chances of paint damage. When everything is installed just peel it off.
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1968 Mustang coupe, Acapulco Blue, 289 2v, C-4, Power Steering.
Hopefully a 1969 convertible or Sportsroof (non Mach or Boss) for next Mustang project
Trying to find my father's 1973 Mustang Grande he bought brand new. 3F04F126773 last known registration and title was in New Jersey, 1982.
1969 bumper issue 
