I swap from a set of mildly ported big valve(2.14,1.81) 906 to a set of MCH CNC ported Eddy 84 CC RPM heads(same CC as the 906) and my old pump gas Duster went from 10.69 at 124 MPH to 10.49 at 127 MPH with no other changes There was around 50 CFM flow differences between those heads also, 260 to 310 CFM
mmmm, so that tells people something perhaps and does suggest that iron heads can make more hp......so I went from a stock head that was dead @around .450>.500"....to one that was good to .600+" and I ran a .650" sft....and got .5 in ET and 7mph...which=+71fwhp
Last edited by rb446; 02/26/2002:19 PM.
1969 'Cuda 446ci, best 9.96@133.9 in 1990 1971 340 'Cuda, best 11.01@122.8 in 1987
There was around 50 CFM flow differences between those heads also, 260 to 310 CFM 
