"around 74+ used pressed in studs with bridged rockers" Weren't these the one-piece-for-two-valve aluminum bridges - bolted to the head, no studs? Around 1980 they realized the mistake of using softer aluminum and changed to a 3-piece steel setup. Ken Quoting Frank Swygert <farna@xxxxxxx>: > Nope. All 70+ 360/390/401 heads are the same for the given year. In mid 71 > there was a change in compression made with a larger combustion chamber. So > 70-early 71 have the small chamber and higher compression than late 71+ > heads. Up through about 73 they used screw-in single stud mount rockers, > around 74+ used pressed in studs with bridged rockers. 304 heads were the > same as far as years and combustion chamber volumes, but of course they have > smaller valves and ports than the bigger engines. > > ------------ > Date: Wed, 26 May 2010 09:06:50 -0700 > From: Jim Blair<carnuck@xxxxxxxxxxx> > > Unless it's a '71 motor. IIRC those heads were 401/390 only? > > > -- > Frank Swygert > Publisher, "American Motors Cars" > Magazine (AMC) > For all AMC enthusiasts > http://www.amc-mag.com > (free download available!) > > _______________________________________________ > AMC-list mailing list > AMC-list@xxxxxxxxxxxx > http://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com > _______________________________________________ AMC-list mailing list AMC-list@xxxxxxxxxxxx http://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com