Same bore, longer stroke. All 199/23/258 engines have the same 3.75" bore with different strokes. The 64-70 199/232 block is 1/8" shorter (or is that 1/16"?) than the 71-89 232/258 block. The other difference occurred in 1972 -- transmission (bell housing) bolt pattern changed to be the same as the V-8. Only 1971 258s will work with the older Borg-Warner automatics. ---------------- Date: Tue, 26 Feb 2008 08:18:01 -0800 From: "Thomas Garner" <Tgarner@xxxxxxxxxxxxxx> As for the 258, for the most part it's the same engine with a larger bore. Both where originally made by AMC. The block and head should be the same...Unless they made a change when they started using fuel injection, but I think the block and head are still the same, though I'm not sure after fuel injection started, some time in the mid to late 80's I believe. -- 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