Thinking about getting some new rims and I'm wondering if a 15x8 -19mm would be too big and rub or possibly cause some major issues. The trucks a 97 Chevy 4dr blazer 4x4 with stock suspension. Currently I've got factory 15x7s with 235/75 ats. Anyone can help?

 

This is the place to go to find the specs on wheels and comparing different setups:

Stock wheel sizes: https://www.wheel-size.com/
Calculator for comparison with wheels with different specs and tires: https://www.wheel-size.com/calc/

Besides basic clearance issues, you also want to look for the "scrub radius." I'm pretty sure it needs to be at or near zero (on the negative side). I'm not enough of an expert to know how close to zero it needs to be to prevent odd tire wear or weird steering behavior.