I see 15" 8 lug wagon wheels on Craigslist from time to time. You may join some Facebook racing groups, someone may have a pair left from running 8 lug rims on their late models in the 70's. One other suggesting is go with the 16" rim and get the 15" conversion caps. You will barely notice there is a difference and if you get the same height 16" car tires you'd be golden. The conversion caps pound on the center ring and 15" caps then can be used.