" From: Greg Taylor <amundaza@xxxxxxxxx> " " Jesse, " There are also a difference in crankshafts. I think it was 1980 when " AMC lightened the 258 and reduced the number of counter weights on the " crank. The Pre-1980 cranks have 12 (IIRC) counterweights and are " heavier. " ________________________________ " From: Jesse <j2sax@xxxxxxxxx> " " I am going to post this on the Strokers Group as well. " " What are the best years of 258 parts to use for srokers? I am getting " ready to get rid of a BUNCH of engines (I have 18 in my shop) but am " keeping the 4.0's and relevant 258 rotating assemblies, a couple of " 360's and 401's. " " I believe it was wrist pin location that was slightly different which " gave a lower C.R.. greg's right, though it might've been '81. the '80s cranks also come in 2 flavors: short snout / serp belt, which is the same as the 4.0 though the pulleys are not, and long snout / v belt. these need trimming, or a spacer, or a stack of washers, to properly install the 4.0 serp belt pulley on. all '70s 'heavyweight' cranks are long snout of course. all 258 rods are 5.875", which combined with the 3.895" crank puts the slug a little farther down the hole at tdc than the 4.0's 6.125" rods and 3.44" stroke. nb. the 199 and 232 ran zero deck, 3.00" and 3.50" stroke, and needed different pistons. the 258's crank was set short of 4.00" so it could share slugs with the 232. after the 232 was dropped, '80s 258 slugs were made taller - zero deck again, or close - and no longer swap. ________________________________________________________________________ Andrew Hay the genius nature internet rambler is to see what all have seen adh@xxxxxxxxxxxxxxxxx and think what none thought _______________________________________________ AMC-list mailing list AMC-list@xxxxxxxxxxxx http://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com