Won't work on the 20R head due to the round exhaust ports and the boltup between the pair. Would have to see the header for the latter.
22R head yes, if a 85+ head; the earlier ones were round also.

http://www.babcox.com/editorial/ar/ar119838.htm If that helps.

http://www.walkablecommunities.org/

Democracy is two wolves and a lamb voting on what to have for dinner. Liberty is a well-armed lamb contesting the vote.

**ubi apis- ibi salus**