Duke, I just got the flow numbers back on a set of stock 492 cast iron heads that i ported and relieved. it was interesting to try and figure out how to do this given that these heads areover 40 years old and the technical data about how to port these heads is mostly from the 60s and 70s. the data is;
Intake Ehaust
LIFT FLOW LIFT FLOW
.100 127cfm .100 49cfm
.200 172cfm .200 95cfm
.300 208cfm .300 126cfm
.400 230cfm .400 153cfm
.500 239cfm .500 167cfm
.600 239cfm .600 163cfm
The flow were taken with 25 inch depressioin
Inyeresting that flow comes on early and is maxed at .500 lift. The relieving process made a significant difference here. Jerry
Intake Ehaust
LIFT FLOW LIFT FLOW
.100 127cfm .100 49cfm
.200 172cfm .200 95cfm
.300 208cfm .300 126cfm
.400 230cfm .400 153cfm
.500 239cfm .500 167cfm
.600 239cfm .600 163cfm
The flow were taken with 25 inch depressioin
Inyeresting that flow comes on early and is maxed at .500 lift. The relieving process made a significant difference here. Jerry
Comment