Allen: From the mounting bosses at the engine block, 5-1/2 inches to the furthest part of the round filter. This leaves 1-5/8" away from the frame. Plenty of room. If I were doing my bracket over again, I would make it set in closer to the engine by making those 3 standoffs a bit shorter, but this worked great. Hope that helps.
Thanks everyone for the advice. Yep, gonna have to go the full route with these engines, no compromise. Expensive, but its good insurance for the next guy who ends up with it. Its not getting any cheaper to rebuild one of these engines, thats for sure!