We're starting off today's post with Incredible Hulk #127 and the reprint from Marvel Super-Heroes #79, and there's no changes I can see other than the blurb being moved to accommodate the UPC code!
Here's another pair with no real changes, other than adding word balloons! It's X-Men #42 and the reprint in #90!
A very slight change when Sgt. Fury #39 was reprinted in #111... the pole Colonel Klaw hits is cut of at the top!
Another barely-changed cover situation occurs with Amazing Spider-Man #127 and the reprint in Marvel Tales #104!
An interesting situation here... Avengers #88 got reprinted in Marvel Super-Heroes #90 as part of the Hulk storyline, due to the crossover (I'm guessing it got skipped in Marvel Triple Action or Marvel Super Action, whichever title was being used for Avengers reprints at that time). Ironically, the cover got reduced for the reprint slightly, plus a blurb was shifted.