1. Our starting point is this clean ZZ4 GM Performance Parts 350-inch short-block. At some point someone swiped all the parts off of it and left it languishing in a corner. Back when it was all together, this GM crate engine was rated at 355 hp and 405 lb-ft of torque. Not bad, but we’re pretty sure we can improve on those numbers without sacrificing street manners or breaking the bank.