Inliners International Forums General Discussion Hi Performance Building a 302 GMC for LSR

Re: cams

Paraphrasing Vizard, the siamese port layout means that there is a maximum practical duration before the exhaust valve of 1 cylinder is open during the intake stroke of the opposite cylinder on those that have both intake and exhaust shared (#2-5), causing the vacuum to be satisfied by exhaust pressure rather than fill the cylinder from the intake manifold. Unlike the usual high overlap problem, this doesn't decay to harmless at higher speed.