[Ol' Ron]

You must have a reason to change anything inside an engine. You have to know what the pat does and why it whould be changed. 2 piece guides are for .312 valves?? also if you change cams you might want to use chevy valves. There are reasons for this and a few dozen other things. You can use the 8BA rods with the Merc crank but you will have to get the assy balanced. You have allot of reading to do.