anyone know a good web site that can tell what parts interchange with other parts? Like if i needed a part, what other models and years i could look in?

This isn't a website, but if you can get your hands on a Hollander interchange manual, they list all the interchangeable parts between vehicles. many salvage yards use these manuals and thy have been around for years. There are many sources to buy these on the web like eBay, amazon.com,and this site:http://www.hollanderinterchange.net/