It really depends on what type of GM engine you are referring to...an overhead valve or an overhead cam. Can you be more specific or perhaps tell us about your application (drag strip, circle track, road race, street, etc). There are several manufacturers of performance heads for an overhead valve 4 cylinder...Deppe Engineering, Fontana. You can use most any small block V-8 head, including the 4 valve per cylinder ARAO head, if you use a Kansas Racing Products 4 cylinder block. Best regards, Gerry
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