G'day RD.
The only straight edge I have is a steel rule so not that accurate. I did test the r/box after machining on 10mm glass mounted in a 3/4 timber frame. All good. So yes both must have been warped. That head had been raced at 14:1 comp for a few years and possibly the 4 outer bolts have been moved 1/2 hole outwards. The 5 inner bolts are 3/8 BSF and the outer ones 10mm x 1.25 so maybe the clamping force has warped it
The clamping force should be equal when all bolts are torqued equally.
Oh well I was running out of things to do in the shed
G'day GB.
Yes it's the first time I've looked at it that closely but that is because it's a different r/box. It may well flex on installation and with .032" gasket paper would have sealed.
Cheers