I bought some of the Canadian roller rockers and shafts. When they got here I looked them over. I didn't think they could look much better. Really good looking. Hemi's are so hard on valve guides, I have to have roller rockers. I measured the ID of the bushing. It was .872". Well, I thought how is that going to fit on a .873" shaft (the Mopar spec)? Yes, I could hone them to fit but that's a lot of work and a normal guy wouldn't have a machine for that. The shafts looked good, and I measured them and they are .871". Again, not to spec but perfect clearance. So really all this was livable considering all the guy wants is rockers that work. So then I assembled them on some of those purple rocker stands and set them on some heads. They lined up with the guides very well. Now I need to put them on an engine and check the sweep of the tip through it's travel. So far I think they are very usable. But you want to run their shafts also, unless you want to hone them to your existing shafts. Maybe I should put them on the test stand engine and do a video. We won't know for many years if they will hold up to 50,000 miles or .800" lift cams. But the price on these is so good, for the 1,000 guys who have street cars, street rods, street/strip cars that don't want to spend $5,000 dollars on rocker arms, these might be great for them. Time will tell.