69-72 wheel question

[canadianK5]

Hi guys, new to the board. First post. I just picked up 4 wheels from the local pull yard. I've got a 72 K5 blazer with pretty ugly wheels on it and have been looking for some stock (or chev at least) plain steel wheels (i like the look). Well, just as I was walking out I saw a 69 two wheel drive and in the back are 4 (6 bolt) steel wheels. Well, I figured they would be great. I get home, try them out on the front, and bang, the inner part of the tire goes right up against the disc brake caliper. If I remember correctly, the line set ticket on the truck read 15 5.5 or something. I'm assuming that has something to do with the rim. Anyway, just wondering if Chevy made different kinds of rims for the 4x4's and 2x4's, and between those with disc/drum and drum/drum. I thought all old 6 bolt rims from Chev were the same. Guess not. I was really hoping they'd work as they in great shape and I actually prefer the skinny tire look. (i.e., 265/75/15). The tire that were on there were 205/ 75/15. Anyway, if I'm out to lunch let me know, as I saw another "deeper" set there as well. Thanks

Marc