Size of hole on engine header

[thewright1]

Hi All,

I know this a really odd question, I searched for it but couldn't find the answer I was looking for. What's the actual size of the hole on the header? I bought some pipes and in my attempt to hook them up, I realized the ending on the pipe was too big to fit snug into the hole. Anyone know what size the header needs to be?

[bikerphil]

The header pipe itself is 1.5" OD, then there's about an 1/8" lip or flange on it to seal to the gasket.