Mike,
My 289 work very well with 10.8 CR,stock rockers (FIA rules),GT40 early heads fully ported 255/202 at.600,245/200 at .550.I spoke with two different companies both different but the approach and the results are quiet the same:
First is David Generous from Camtechniques,the other are Buddy rawls (
www.wighat.com/fcr3/ impressive site about camshaft,sometimes difficult to understand but very clever.
About my camshaft specs:
260°@.050 inlet
255°@.050 exhaust
My E/I ratio is very high at low lift average 92% atleast up to .300 lift cylinder pressure is compromise because the exhaust flow begins too early and loose some velocity and scavenging potential and need reducing the exhaust seat duration will achieve is holding the cylinder pressure a little longer,it will also reduce overlap.This should produce better inlet filling and cylinder pressure potential,which will boost VE,and therefore torque in the lower RPM ranges,regards,Bernie