Rigsby . I reworked one that someone had started to install. it had a BBC with headers. I actually had to cut out #1 primary tube then install shaft and reroute primary tube closer to block to clear shaft. hope this helps. if not call me and I see if I can explain better. Bryan 931-623-9512 ALLEN FABRICATION SERVICE . send me your e-mail and I send you a pic of what i done.