I tried industrial supply but they didn't have the correct taper when I was there. The correct taper is 7 degrees (3.5 per side) or ~1.5" per foot. They may have them now, but they didn't when I was there and the guy at the counter didn't know what's up. I also tried Mcnees(sp?) and they didn't have any in stock. I ended up going to www.stockcarproducts.com and it was delivered in a couple days. I had to cough up $80, but it was money well spent.