need home maid header advice...

[rainman]

Bolting it down will help with the warp-age too somewhat.
I think I would split a flange that long into sections, however that might not be possible looking at it again....

Good point Dirtyrat, if you had an old head to work off from it would be a lot easier!!

 

[jfg455]

due to the warpage issues I bolt the flange down to a large piece of steel (I use my welding table) and I add a piece of sheet metal under the center. This gives the flange a slight bow the opposite way that the welding heat will pull it back too. I usually get it almost perfect. Local machine shop has a large surface grinder that will flat it out perfect and they only charge me $35 for 2 headers.