EGT ports

I have a new (old/unused) IO360-A3B6 that I’m trying to install (RV7) using a Vetterman exhaust that has the egt ports already drilled in different locations. Cylinder #1 is 1 1/2” from the flange, #3 is 1 3/4”, #2 is 2 1/8” and #4 is 1 1/2”, have called Vans they referred me to Vetterman who’s mailbox is full,and Lycoming said 2 to 4 inches from the flange. No idea if the previous drilled the holes or if they came predrilled. Hopefully I am only going to have to plug weld two holes but probably will be four. This has been a fun project !
TIA, Kirk S.

I don't know of any Vetterman exhaust systems that come pre-drilled for EGT probes.
Rule of thumb is the closer to the flange the faster the reaction time, but shorter longevity of the probe.
All probes should be same distance from flange.

EGT holes

Mel is correct, we never predrilled any holes for egt, but I certainly welded shut many that were drilled in the wrong place and sent back to fix.