John: That was Brewers Performance asessment on this as well. Yes thats my plan to do a modification on a flywheel. I'm a little bit concerned about how much play is in the original that came off the 383. When installed you can move it up and down and hear it clicking against the flange, there is so much play in that. My understanding is that this should snug fit. Like you mentioned it locates the flywheel to the crank flange, not the bolts. With that in mind, I'm going to have a machine shop I work with daily at my job to chuck that flywheel up and get the hole out to 2.19 from its present 2.16 and use that on the 440. They can get that exactly centered. Then get another flywheel for my 383 when I get ready to put that original motor back in the car after rebuilding. Probably a new one from Brewers. They were allot of help with this so I plan to send my business their way later. Trying to be driving that 68 Super Bee before Christmas. Its been a constant year and a half project thats still ongoing.