[mg2166]

Niles: The measurements I am able to make don't point to anything being wrong. No smoking gun.

Steve: I liked your idea about checking the sidepipes against each other, so I pulled them and everything checks out perfect.

After talking with Brett at Everett Morrison, I think I have a solution. When EM encounters this problem, they use a wedge shaped spacer between the header and the exhaust flanges. A 1/16" taper at the flanges will create about 1/2" at the exhaust tips. Not as much fun as Carlo's method but less chance of setting the garage on fire.