Just replaced the factory dizzy on a 1990 5.7 (non roller cam) with a Summit house brand billet unit. It's making a heck of a whining noise now. I've taken measurements between both units and they are pretty much spot on with each other. The only thing I can see different is the "top land' area of the new dizzy gear is a little more narrow. Also, the I.D. of both gears are .491". Any ideas?