426, VG thinking as you never hear to check all of em since (for some reason) it is assumed that if one is good then all of em are (might be the CNC repeatability precision I would assume). Yes you can do any cyl & the reason doing #1 is common is the wheel shows TDC when the (#1) piston is at TDC (makes for easier math). On any of em just find true TDC of that particular piston (a # on the wheel) then see how far away from that point that the lobe peaks at such as 102 ATDC. Try #6, get its piston on TDC compression then find exact lobe peak & note how many degrees that that is past piston TDC, this is the bottom line including crank keyways/sprocket keyways & for example 102 degrees lobe peak is closer to the piston TDC (more advanced) than 106 is cuz if you are 102 ft away from your door in a rainstorm you are closer than if you were 106 ft away.