The reason for this, and this is only a guess, is they don't want you pounding at there door mfing them to death in the event the 904 fails. Been at my friends shop numerous times when a customer walks in and with the I am building a 600 hp small block & am going to hit it with a 300 shot of nitrous and I want to run a 904 story. Right away my buddy will try to talk you out of it because his reputation is on the line with every job he does. And which unit would be more likely to fail in the above situation, a properly built 904 or a properly built 727? Could be that is how they guy that told you to run a 727 over a 904 is still in business after 30 years?? If he told you to go with the 904 and you scattered it all over the track who is going to be the first person that gets blamed??