soba_03,
The bellcrank pictured isn't something special, it's a stock Chevrolet part that should be on your engine...it has to be in order for it to work.
You haven't mentioned what exhaust system you are going to use. I think the linkage from bellcrank to the Offy piece is a cake walk unless you are dealing with Fenton exhaust headers. With the Fenton's, you have to turn that piece of linkage from the bellcrank into something that resembles rigatoni to make it work.
Stuart
