After surveying the new Edelbrock castings and discussing the design features with the engineers, the conversation naturally turned to flow numbers. They can vary considerably from bench to bench, and some manufacturers, and especially head porters, throw out impressive specs, but the bottom line is: How much more flow do we get for the money? We discussed how much better the Edelbrocks flowed than a production head, and mentioned that we happened to pack a stock casting; "What do you say we flow it?" The R&D crew at Edelbrock said, "There's the bench, have at it." The result is an independent and unbiased flow comparison between a pure stock 906 casting, considered by many to be the best-flowing stock regular-production big-block head, and the new Edelbrock Performer RPM-on the same bench, on the same day.
The results speak for themselves, with the Edelbrock showing a substantial gain in flow throughout the lift curve, both on the intake and exhaust. The numbers we obtained were identical to the figures given by the Edelbrock engineers, proving the integrity of Edelbrock's claims. It would take an outstanding modified production head to approach the numbers of the out-of-the-box Edelbrocks. Dollar for dollar, the amount of porting alone would likely cost more than the full price of the complete ready-to-run Edelbrocks, to say nothing of the cost of new seats and guides, valve machining, springs, valves, etc.