[wilf leek]

Tony - you make good point about having to "squeeze" in larger dia primaries on stock exhaust port configurations - my own are necked right down, and I use allen-headed bolts instead of hex heads to make a little bit more room. This seems to work quite well, and I drilled them so that I could safety wire them to stop any rotation.

If I ever change these heads, I would look for some with the alternate bolt pattern ( Gulp - is that a "chevy" pattern??) to allow the use of bigger primaries without any "necking down" at the flange. We live and learn I guess.