THAT looks much more in proportion with the wheel opening, don't you think? Are your wheels the 1/24 Monogram "Centerlines"? If you're having trouble finding 1/25 choices, here's a couple of possibilities that open up way more choices for tires. The chrome ones are found in the AMT '59 El Camino, and are all the same offset and have the slightly convex center area much like what you have. The unfinished wheels are a deep and shallow set found in AMT's '55 Chevy, and have a flat center.