Most states would just recreate the food stamp program at the state level, as it is one of the more effective welfare programs, despite its shortcomings. Plus there will be pressure from grocers and the like to keep it.
And without very specific and guaranteed guidelines and restrictions (which would render block grants pointless), they'd likely create variations of that program that are much harder to qualify for and maintain. You should see how difficult it is to qualify for Medicaid in Georgia and other states following the bare minimums; hopefully, you're a pregnant female with 12 dependents and make $5 per year, because that's about what it takes. The federal minimums are ridiculous for it, as they'd likely end up being for SNAP et al.
