Hello everyone! I own a 91 Indy 500. Sled runs really good. I have one problem. I have an awful vibration at 3000 to 4000 rpm. Anything above and below that it is fine. I think that it is the crank bearings. I have rebuilt the clutch and that didn't seem to help. If anyone out there has had this problem, let me know. And if you have had it repaired, how much?