RWA1691 2.3 Tall deck block is similar to the old Ford Motorsport M-6010-B230 block. This particular block needs to be used with an external style oil pump, the oil pump mating surface has a machining flaw and will not allow a stock style oil pump to be used. These are stronger than stock, they are cast with higher grade iron. Cast iron Large main journals Billet main caps Roller aux bearings (requires modified or aftermarket shaft) 9.025" Nominal deck height ONLY ONE IN STOCK