+1 on them fitting. The soft 8 style in the summit brand fit on my '06 even though they weren't supposed to. I do only have about 1/8" of clearance with my front calipers though.
The wheels will fit fine, I would go with a little taller tire though, those will look really short on your truck. A 245/70/16 has some good width and will fill the wheel wells better.
04 Silverado ext cab. 4.8, K&N, Pacesetter lt's, e cutout, slp loudmouths, Wheatley tune.