Here are some planes for a small Marine Engine that supposedly can be built in a week end, I've been working on mine for 2 weeks already.
If you can figure out how to make the upper cylinder covers I would love to know as this has stumped me so far.
Regards
dgehricke
Heres a web site for a 4 cylinder dual overhead cams Offenhauser racing engine
< http://www.ronsmodelengines.com/Offy.html >
good luck
Regards
dgehricke