I live in Australia and no true 57 or 58 Fords were offered here. Ford Australia continued to offer the 55/56 Ford shape with yearly upgrades for 57 and 58. We did get back in step with the 59 Fords, after missing out on these two yearly models. Regarding your question, I believe that any Frame from the Custom series would be interchangeable, as the Station Wagons shared the same short wheelbase with the Custom Sedans. For two years, 1957 and 1958, Ford cars in USA were offered in two different Wheelbases. The Customs and Wagons rode on a 116 inch wheelbase, while the Fairlanes were stretched to 118 inch. You could also use the Frame from a 57 Ford Custom. The Fairlane Frame for either year would not be suitable. These are my thoughts, so it would be helpful to get someone local to confirm my comments.