Thanks to all those who responded, and especially thanks for the links with more information.
Just to bring this back to the original question, the picture I've attached is the reason I asked about what issues there would be with Fenton headers. This picture is from the Classic Parts catalog. There is a clear warning about not working with the headers, yet people have done it. Just trying to figure out why they put this warning, in capital letters no less. Maybe it's just the lack of a heat riser on the headers??
Also, horsepower gains really aren't my priority. In fact, my concern would be more of a loss of horsepower from improperly tuned/synched carbs than anything else. That's not to say I wouldn't welcome more power if I could get it, but I'll openly admit that I'm really after the eye candy cool factor! (much to some of your dismay!)
Anyway, please continue the horsepower conversation, and if anyone knows why they put the disclaimer in the catalog, let me know.
