Plano Model Products planomodelproducts.com has really nice photo etched brass/stainless Apex, Morton, and Peterbilt new style oval pattern grille sheets for 1/24 and 1/25 trucks. It is found on their website under HO scale - scratch builders materials. Ben at Class A Resin also has grille detail sets for Kenworth and Peterbilts, if that is what you're building.