I couldn't set it up at 104, by looking thru a spark plug hole with an endoscope camera, it looked like piston to valve clearance was going to be tight on the "eyebrow" on piston top. Ended up at 106.5.for intake centerline. I only got one pass, had the T-stop set a little more aggressive than with my old motor, it ran 10.309. (Denver index is 10.50) What happened was when I got back to the pits, my crank bolt and the 5-rib pulley that drives the alternator were long gone. I've heard of other racers having those kinds of issues, some guys even losing their dampner. I've been running that setup for 17 years and never had a problem until yesterday. Now I'll be adding a tab to the crank pulley so that it can't unscrew when the alternator is under load. Another thing I see with this motor: I've got flat top pistons, 915 heads that have not been cut, 451 cubic inches. Some articles that I've read say that this setup would net 11 to 1 compression, however, when I do the math it looks like I don't have much over 10 to one, and that's not counting anything for the small valve reliefs in the pistons? Other particulars: Chrysler Lebaron, round tube chassis, car weighs 1940 lbs. without me or ballast. OLD 451 engine built in the late 1980s, the current cam is the Crane F-280/430-10, Powerglide 1.80 low first gear, and 4.30 rear gears. A;lso, Crane gold rockers.