Hi guys. I've just bought an engine. It came with a B&M blower. How do I tell what it is? There's no numbers or markings on it. Does anyone have a pic of a 420 and a 250 Mega Blower? I might be able to see which one mine is. Also, it has a serpentine belt on it, and was wondering if I could change it to a belt like on a 8/71 blower. Thanks for any help.