no. center mounts are different.

I have found a couple on eBay. They seem to be getting more expensive though even for used ones in good shape.
71v8Pinto

You can put a 74-75 grill in a 71-73. It will just sit out closer to the front edge of the hood and makes it hard to use the hood latch. you would also have to fab a center mount point. A lot of V8 swaps used that grill to gain some radiator space. Most of those just pinned the hood too though.