any OE flexplate is fine (pretty sure the 904's and 727's used a different one so grab the one for your choice of transmission). You would be using the OE externally balanced torque converter with the weights on the front flat face side of it. For a performance app I would have everything internally balanced & you can even have that done with keeping the offset external balanced harmonic dampener in the front then you can use any performance (or OE) internally balanced converter & not have to be concerned with balance issues as aftermarket ones are all internally balanced. for the nth degree lightest bobweight I'd get a neutral (318) harmonic dampener/regular neutral plate/your choice of internally balanced converter OR if external balance is the plan just get the B&M plate (10239 for a 904) & keep the OE dampener up front & externally balance it then you can use any performance/OE (no front face weights) neutral converter you want.