Tallest front tire on a duster

I tried a set of 27" GoodYear front runners on the front of my Demon. They wouldn't fit. I ended up with 26" front runners on it. I have a freind that has two Stock Eliminator Dusters. He runs a 27" on the front & 30" on the rear. I asked him how he did it, He told me alot of money & good body shop. His looks stock until you take some measurments.