Posted: Sat Aug 29, 2009 5:34 pmHey guys i just finished porting a set of Dart pro-1 alloy heads and although i found a nice improvement in flow, i have to say i was very disappointed with the quality of the casts!! There was such a huge obvious difference in the guide bosses from one end of the head to the other, i had to wonder if the people who made the cast are blind or retarded!! 
The port with the smallest boss flowed 156.7cfm @ 10". The port with the largest boss flowed 146.4cfm @10". It took me 2 days to equalise all the ports (grinding only the bosses) and now they flow 158.2cfm @ 10" and are 95% efficient. Goes to show you cant take anyones word for it and also highlights just how important flow-testing really is!!!!
The port with the smallest boss flowed 156.7cfm @ 10". The port with the largest boss flowed 146.4cfm @10". It took me 2 days to equalise all the ports (grinding only the bosses) and now they flow 158.2cfm @ 10" and are 95% efficient. Goes to show you cant take anyones word for it and also highlights just how important flow-testing really is!!!!