I don't think the OEM rims have changed over the years so: the stock rims run 4.5" of back spacing. That will get allow clearance for the inside. You can run more, and people have run 9" wide rims up front and tucked them. Clearing your fenders will be a different story.
I measured my truck my self for the rears that I want. You can do the same with your fronts. Mock up your rim/tire combo, cut a piece of wood to your overall size tire/rim combo and bolt it to your rotor. Now tape some string with a weight at the bottom (plumbob) to your outer most point and the innner most point. Make sure you pick the first thing your tires/rims will hit. Now you can take measurements. You'll be able to get the overall width that you can fit plus the maximum backspacing you can run. You'll want to leave a 1/4" to 1/2" for measuring error and some clearance.
They make a tool you can buy for doing this but this works too. I found out I can stuff a 12" rim in the rear of my Ranger if I really wanted to. My plan is to put a 10" wide rim back there with 6.5" of backspacing. I just need the money to buy them LOL
James