You can make it work but it's only muffler back. Just guessing, but you'll likely lose your spare. The majority of restriction on the stock system is the Y pipe.
Kind of like hooking a garden hose to a piece of 3" pipe with a fist full of adapters. It won't flow any more water.
Basic fluid dynamics.
oh im not looking for any perfomance gains. Its an old winter beater truck. Right now I dont have any exhaust from the cat back. It rusted out. Im just looking for something to quiet the sound down, make it sound less like a tractor. Spare tire is already gone anyway, so thats not an issue for me either.