to be honest the 275/40 sumitomo tires i got are listed as a 9.5" recommended rim size on tire rack, but the thing is when you put them on a wider rim they will try to sink a hair in the center of the tire so you could probably go with some 285/40 tires and it be the same as the 275's on a 9 inch rim, i got this little calculator you can mess around with to decide what size you want Tire size calculator
BV heads, P&P lower, windstar upper, comp 218/226, 4.2 bottom end, 3k stall, flow 40's, O/R x-pipe, Pacesetter lt's, Xcal2, 65mm tb, CAI, 8.8 w/ 3.73's, MM LCA's
coming soon: blower cam and intercooled M112
dealer for Ortiz Performance; tunes, cams, etc. PM me!