I had a Reflex gasket on my last manifold and it worked well, however the leak was at the heat riser. I had another manifold which had the heat riser removed, and I had it sperated and milled. It sounds very good at idle and when I give it throttle. I sprayed water around gaskets with no difference. It's when I hit the road around10 mph under load that it makes a chug chug chug noise.
