Can you put a Chevy silverado grill on 88 Cheyenne?

No, you can't directly put a Chevy Silverado grill on an 88 Chevy Cheyenne without significant modifications. The body styles and grille mounting points are drastically different between the two generations. The Silverado is much newer and has a completely different front end design. You'd be looking at major fabrication work, potentially including modifying the core support, bumper, and potentially even the fenders to make it fit. It's not a simple bolt-on swap.