Ran 4.30's in an 04 gt. Not the same by no means. That car LOVED them.
My best friend has a 12.50 89 lx that runs 4.30's. Its a monster but the pushrod cars don't like 3k at 70 on the hwy. Takes him forever to get anywhere far.
If its just a toy(like my buddys) and your not worried about running out of gear then do it!
EDIT: b/c I know someone will say it as well. You can run a 28 inch tall tire (stock is 26) and get away with a taller gear but if its a GT you will have bad rubbing issues and have to roll the fenders even on an lx.
We really need to know what you plan on using the car for. street/strip. Drag only? Daily driver?