agreed on above post, its just a pressure demand valve. the effect of proximity to the big end mentioned would be very complicated to predict, but ultimately in the state of tune of these engines I doubt it would be a measurable effect
obviously its in no danger of hitting it in any design with a reed stop, just in case anyone was thinking that
Ive never seen a reed without a stop plate

p.s...Av8.you got the pressures the wrong way round tho, .......gawd, im gonna get it now...next mistake I make[sm=spinnyeyes.gif]