360 build

Only if you install it correctly. By that I mean aside from the dismounting of the stockers, plus re-installing the Speed Pros on the rods, you will need to have the assembly re-balanced as the new pistons are heavier than the stock ones are and I'm sure the assembly was not balanced by the rebuilder. (this is normal in stock non-performance builds as the parts are all factory replacement design so there isnt a "need" to) If it was me I would be leaning towards replacing the pistons with a performance flat top hypereutectic and then have the assembly internally balanced so you can run any convertor and any stock flex plate with it. Since you're changing the cam you're voiding the warranty anyway. Betweent eh pistons and the balancing you're probably looking at another $500 into the shortblock. But the you could run the Aerohead LA heads or something like them which I think would save you money in the "the big picture" over running a Magnum design.