BarryP, First off Welcome to Stovebolt!
From your description it sounds like your new to you truck already has some mods from original so it's not possible to give you much advice without seeing what you actually have for an existing rear axle. To help folks help you, take and post some pictures of your axle in your thread (and any identifying info you can find) using the guidance found in this
helpful How-To guide.
Looking forward to further info and pics so we can offer some help.
