"The 4.0L has a 0.125" larger bore and the block is about that much wider on the right side (87-90 258 blocks use the same outer casting and are also wider)." Swygert, Francis G MSgt 436 CES/CECM <?> As to the inner castings, since the cylinder locations are same as the 4.0 > are the cylinder walls thicker since the pistons on a 258 are smaller diameter ? =Bt= milnersXcoupe "The Heretic" _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list