Oh kay, here is a question that I don't think anyone else has brought up.
Is this for an In-Line 6 or a V-6, 71? The V6 version might not be as common but they are out there and the V6 would not use the same blower, actually a V-12 would use a pair of V-6 blowers.
Also might be good to know if this is for a "naturally aspirated" or "Turbo Charged" engine? That makes a difference too.
One really needs to be very careful when playing with Detroits as they are one of the most adaptable engines out there. If someone could come up with a special application Detroit or someone would modify one to fit. Many modifications can cause parts to not interchange as easy as one might hope!
Want one laying flat, no problem, want blower on left and cam on right, want cam and blower on the same side, want blower on right and cam on left, want two sitting side by side driving the same generator, want one turning clockwise and one counter clockwise, and on and on.
Almost forgot want flywheel at the bottom and crankshaft pointing up, that's been done too!