Man I, thought this would be cut and dry but I guess I'm missing something. Here's what I have now: 1990 1/2 ton suburban. GM 10 bolts. I want to do the 14 bolt conversion, Why is it nessesary to obtain the backing plates from the 14 bolt SF axle? Why cant you use the one that comes with the FF? Also, their are 3 drum sizes for the 14 bolt FF. 13x3.5, 13x2.5 and 11x2.5. I havent heard mention of this on this site before. The 13 incheres are significantly more expensive than the 11's and so are the parts. I have new 15 inch tires so I am assuming that the 11" drums are my only option. I could take the tires back and go 16" if there is a great benefit to going with the 13" drums. Also there seems to be an issue of left or right parking brake. Thanks.