Post Your Straight Six Pics!

[RichardJ]

For tube headers you would be wise to replace those locator pins on both ends of the head with bolts or even better, threaded studs.
Every hole down the side of the head is threaded 3/8-16. The heads originally had those end pins and the third hole from each end had a threaded stud for a 3/8-24, nut.
Originally they had both long and short clamping bars for between the IN and EX runners. I found extra short bars and used only those between the tube headers and a Clifford manifold.
I put studs in all eight holes and it makes it a lot easier to hold everything in place for assembly.