Wendell,

I've yet to see ANY header line up absolutely perfectly down the center of the fuse. Even the ones for my rear exhaust OS 1.40's were not perfect. It really doesn't make any difference though. Even the short hatori header and pipe I'm using now, i'm not 100% they are dead center on the fuse. I know that they certainly weren't aligned with any special tools. Mike and I set the header and pipe where it looked close and drilled the holes. Makes absolutely no difference. On the old pattern planes, it wasnt unusual for the pipe to be significantly offset from the center of the fuse and headers had to get around nose gears and such,

Arch