I think that you will never recoup the money spent on getting a 6L80E installed to justify the cost from gained MPG.
Is it doable? Sure, won't be easy or cheap.
Better off getting a gear vendors unit for a double OD if its that important to you.
Is it doable? Sure, won't be easy or cheap.
Better off getting a gear vendors unit for a double OD if its that important to you.