The different bellcrank position is to accommodate the difference in exhaust manifold shape. Later model manifolds are angled toward the rear which requires the bellcrank to be moved to the rear position. If you have the angled exhaust and the forward bellcrank position, you might have to do some creative linkage fabrication between the bellcrank and the carburetor.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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