Oil pans are another area that used to be problematic. When working with a stock subframe, swappers were forced to notch and modify factory LS F-body pans. Today there are quite a few options from companies like Canton, Autokraft, Milodon, ATS, and others. There's also a chance that there's a GM pan that will work in your particular application. A great resource to reference is the website www.ls1tech.com where they have a "Conversions and Hybrids" section just for swappers.