That's how I did mine. 2 inches. I didn't want it covering the marker light, and if the hood sticks out past the bumper, it defeats the purpose of a bumper...
If you are able to do the swap, I highly recommend it. Don't mean to be controversial, but the big bumpers ('74-'77) look so out of place on 2-door Mavericks/Comets. These cars were never meant to have those when they were initially designed, so they were an after-thought when the Federal government mandated it years later, and it was poorly executed. I say that because if you look at the GM and Chrysler "5mph" bumpers on their '74-'77 models, they look leaps & bounds better, and are more integrated into the cars rather than just slapped on...
I really do like the smaller bumpers. The one I bought years ago is hashed and the repopped ones are too expensive for me at the moment.