Look at the center of the exhaust manifold gasket, between the paired cylinders. If you see a single stud casting it is early (84-down), if you see two (with a center hole for earlier compatibility) then it is late (85-up).<P>Closed chamber means the combustion chamber around the valves are closed in, compared to the earlier design.<P>No, there are other differences besides the cams (are the cams different?).<P>Regards,<BR>Kenton<P> <BLOCKQUOTE><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><HR>Originally posted by Andy:<BR><B>Howdy,<P>Would someone please give me a quick visual way to distinguish the pre '85 22R cylinder head that uses domed pistons and the post '84 "closed chamber" head. I guess I don't understand the closed chamber term. Also, for the '85 and later 22R and 22RE cylinder heads, is the ONLY difference the cam durations?<P>Thanks,<BR>Andy</B><HR></BLOCKQUOTE><P>