Straight Pipes

66plyValiant said

I wouldn't recommend running without mufflers, since they are meant to restrict flow running without them will allow the engine to flow more; but also cause the exhaust valves to get much hotter then there normally suppose to run

besides your local bylaw officers may like to target you

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must be why all things not on the street dont have mufflers... the valve temp in only in relation to cooling system efficiency and combustion chamber temp.

but with open headers you do want to let the motor run for a minute after a run as to not suck cool air and crack a valve or seat, but thats with open headers, no exh