Bob, I saw your post about flanges before. At the time of order and even after I received my kit, I did not have my motor or know what heads I may end up with. We can't remember or not if Alec asked me before welding them up.
Would it have saved me some aggravation had we gone with 3" spaced flanges had I known, absolutely, but they are on now and going to live with them for a long time. I used ARP bolts, 3/8-16, 1" in length with 5/16 12-point head.