Re: 15 by 7 inch
I've got 15x8s on the back of my 81 with 275/60-15s,it also has a 9" with drum brakes,I'm thinking I have 4" back space and there's not much room between the tires and inner fender well,in the FAQ on the main page quotes 15x8 with3 1/2 bs and 275/60s
as being the biggest wheel tire combo on a stock Malibu,of couse I have read where others were able to sqweeze larger in with some creative hammer work and trimming or rolling the wheel well lip,I think 4 1/2" is pushing it myself,all I can say is measure carefully and remember that the tire bulges out past the rim with 60 series tires and gets less as the numbers go down as in 50 series,smaller bulge,40 series smaller and so forth but I think 50s are the lowest profile you can get for 15" wheels,hope this helps,Later,KillerDave