Cor Blummy , looking for a picture of a good perforated Brooklands Can. . THE pOMS HAD NOISE REGULATIONS THERE PRE WAR ( yea , That War )
Brough Superiors , Velo's & J.A.P.'s . But as we found a picture of the renouned Grindley Peerless
multitudinously drilled . . .
A similar effort ( the Muffler assy ) might be worth a try .
On a Straight Tube , however , multiple outlets at multiple distances would generally be though to provide a wider power band / broader tourque curve .
Hence ones dozen 2 mm holes , maybe two rows over 1 1/2 inches .
Theoreticaklly , a crayon line down your header - should burn off at wave points first . Furthest Aft ( due to multiples ) should be ' tooned length '
for something ,
Likely varies with R P M . Assume choosing RPM before observing burn might be the best bet .
Been meaning to drill my header for the Irvine 40 & K&B 7.5 thus , for the S6B.