Joe, the leter in the center of the date code should show if it's a 232 or 258. A would be a 258/1V (71-79), E a 232/1V (70-79), G 232/2V (70-74). I show a 258/2V, but not until 76 (76-89). There was a patent dispute with Buick. 72 would be shaft though... unless the engine plant made the change by calendar year, which they sometimes did, then late 72 models would be bridged rockers even though the TSM doesn't show them. 73 models had bridged rockers, 74 back to shaft, then 75 back to bridged after the dispute was settled. Again, changes at the engine plant doesn't always correlate with model year changes, but the above is what the TSMs show. I do recall that one of the changes occurred during the model year, and that the switch back to shaft covered roughly 18 months of production. I don't know how it got settled -- if AMC paid a license fee, traded out something they had a patent on, or proved the design was slightly different or the patent wasn't valid. ------------- Date: Sun, 18 Jan 2009 18:05:33 -0500 From: Matt Haas <mhaas@xxxxxxx> Subject: Re: [Amc-list] What is it? 232 or 258 72 was about the time AMC switched back and forth between shaft and bridged rockers (I think there was some sort of patent dispute about the bridged rockers going on then). The stroke and (maybe) rods should be the only difference between the 232 and 258. -- Frank Swygert Publisher, "American Motors Cars" Magazine (AMC) For all AMC enthusiasts http://farna.home.att.net/AMC.html (free download available!) _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list