I think the cam's fine for what you're talking about. No "need" for a convertor but I see your point. I like the Mancini Racing convertors.. Cheap and they do what they say. I have a few intakes, including an iron 318 Marine. Personally, find a 318 Performer and call it a day. I had a similar 318 with X heads and stock iron intake that I ran for several years. Passed emmisions back then too with the Comp High Energy 268H.