I have an article describing the Indy stock block engines. It states a special 401 casting with 3.75" bore for an engine size somewhere in the 200-250 cubic inch range. Will have to look up the article tonight for more details -- it's easy to get to. It also mentions aftermarket main caps. Has to be that block casting unless the block has been sleeved. ---------------- Date: Thursday, December 14, 2006 10:52 PM From: Nick ALFANO <71amx@xxxxxxxxxxxxx> Anyone have any information on a 401 block with an X above the displacement casting and only a 3.750 bore. There is also 401 cast into the intake valley. It has very large water jackets and splayed main caps. It might have been an endurance engine for one of the racing sanctions with a long stroke and small bore. _______________________________________________ AMC-List mailing list AMC-List@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list or go to http://www.amc-list.com