Thanks for all the photos and ideas! After looking at the photos and various methods used to make this connection, David (125Shifter) and I came up with this design which he so graciously machined up for me.
There was a giant red o-ring left over from the gasket kit from my rebuild and it fit the TB almost perfectly and with the 0.05" of clearance from the flange to the TB the seal is TIGHT...the tapered set screws keep it locked in place.
This fitting will get the 3" pipe welded directly to it and a rubber boot will terminate at the IC hopefully making it a little easier to access for removal.
