Originally Posted by rrrdad
yes it is a bit more than I want to spend bu that is a descent price.. What is the max CFM you can get out of stock heads? and do you know the max lift on stock heads? Thx MM
Here's the answer on the stock 781 heads. i copied this from another forum, but they don't do much in performance compared to today's alum heads.
The heads now have 2.190 / 1.880 Manley Super Duty Stainless valves, full port work and the valve spring pockets are cut for 1.625 dia springs. The egr ports are filled. The head guy never did fill out a flow chart for the heads, but did say they flow 320 cfm on the intake @ .700 lift and 240 cfm @ .700 lift on the exhaust. About the only thing left to do to them is angle mill them. I've thought of doing it, but I think I'm done with them. I want to upgrade to a set of AFR 335 cfm heads.
Here is the flow charts for stock as cast AFR 325's, you'll note that they flow 384 CFM out of the box @ .700 lift. That's more than Brodix BB2 Extra heads flow fully ported. You can also see the heads cost $2200.00 from Jegs which make that deal even better on the RJ advertisment especially with extra parts.
http://www.jegs.com/p/AFR-Airflow-Re...56123/10002/-1
Zip.