I have seen many of the 4 cylinder engines running on a couple 2 into 1 headers and 2 canisters and it seemed to work fine. I fly with Dave Sullivan on a regular basis and IMO if he says it can be done then I would trust him. Not only has he advised me on our big gassers from time to time but he has also helped me out tuning the YS 4 strokes. Dave is an engine guy no matter what the engine is. I have nothing nice to say about Jtec so I will let them alone.