hi again,to tell the diference between a 904 and 727 with out having the to along side each other{727 is much bigger than a 904} is the shape of the base pan, on a 904 the pan is square with one corner cut at 45deg angle, on a 727 the pan is also square but under the dip stick the pan is push out is a round shape.but if you want a quick slantsix stick with the 904 it uses less hp to get moving, i have drag with both and everthing being equal the 904 is 2tenth faster