Can anyone point me to a research website or doc - related to the exhaust for a 79 XL 500? I am certain that it's a 79. And member ossagp said that an XR header will fit the XL which is great. However, how far can I go in years to where it will still fit? I'm fairly sure it's the same for 79-81. But - can I run say an 84 header pipe on the 79? I just to need figure out which years run the same header pipes. Thank you in advance.