57 head hu? Well I learn a bit every day
Does it have the oil line under the side cover?
I got a dual Weber/Holley setup on a Offy intake
Got my adaptors from Tom Langdon and they may fit your intake also. Talk to Tom on details, he`s the guy who also may solve the bolt mystery.
http://www.stoveboltengineco.com/index2.htm have fun and many greetings from sunny southern Germany, Frank
