Nice answer... concise and to the point... ;-)) -- Dave G. KK7SS DN06ig '65 Sprite - work in progress '76 Midget - nearly ready On 17 Aug 2010 at 20:20, Mark Haynes wrote: > This makes the use of a tuned exhaust (header) more desirable because it helps > scavenge the exhaust gases, reducing the contamination of your intake charge.