A budget upgrade to the 7.5 is to swap in the 28 spline limited slip diff. from a 4th gen Camaro. Then new Moser 28 spline axles for a GN (stock axles for a 8.5). It makes it strong enough for everything but huge power and slicks. There is at least one member on here that has raced that setup without issue.
Here is some more inspiration for you....
https://gbodyforum.com/threads/78-monte-4-speed.63280/
Here is some more inspiration for you....
https://gbodyforum.com/threads/78-monte-4-speed.63280/