I had an Isky E4 in a HP 273. It behaved very much like the stock HP cam. Specs on stock and the E4 were very similar. Probably yielded a bit more power but since the lil 273 gets it''s power from RPM it was hard to tell just by feel. It sounded the same which was a plus for me. Overall, if your looking for a near stock replacement I think it's the one.