CONGRADULATIONS on your purchase.
i hope you bought with intentions to keep, because 71 and up B bodies don't get much love and don't bring high prices like the earlier ones do.
not to criticize but unless it's a GTX, 72 roadrunners didn't have 440's in them from the factory. only GTX got a 440 from the factory in 72.
hope the 72 only parts were included when you bought it, especially the complete grill.
the grills are made out of unobtainum and really nice and complete ones cost more than 71 cuda grills.
I though in 1972, the GTX was no longer it's own model, but rather a package that was added to the Roadrunner. I had both a '73 and a '74 Roadrunner with a matching numbers 440, but they both were equipped with the "GTX" package.