[olddog]

If not sealed, it will leak exhaust gasses that will get in the passenger compartment and make your clothes stink of exhaust. It is possible to become ill and even pass out if the gasses get thick enough, which is not likely with the open cockpit. However I wouldn't bet that it is impossible, if the wind and speed were just right.

Having dealt with this, it is my opinion the builders who sell this should be shot. Do yourself a favor and weld flange plates on your pipes. Make gaskets out of soft aluminum.

Yes I tried copper RTD and several other things suggested. They were temporary fixes at best. Some may fit tight enough to seal, as there are people who claim they got them sealed up. I had no such luck.