Air flows: Street Dominator & Edelbrock RPM

When you start porting any intake manifold there are such a wide range of options each time you just cannot say this is what you'll get if someone else ports the same manifold. What do I do to the plenum? Do I raise the roof here or change the curve on the inside wall? And the dual plane is a whole new snake pit.

Suppose you get an Edlebrock RPM to 'fix'? As in this case, the manifold we were given to work with was a new RPM and the owner had never ported anything before. In his attempt to gasket match the intake he accidentally ground right through the roof of the port.

No porting was intended, so our goal was a quick weld repair and then gasket match and blend as best we could. As we had another RPM intake that my father had gasket matched before he did almost 20 years ago, it showed us that gasket matching on a RPM will give substantial flow increases. Horsepower increases on gasket matching the RPM? Don't know. Though we had an OOTB RPM we didn't get to dyno test it on this engine.

What we did get to test was a mildly ported Street Dominator against the repaired RPM. I will attempt to expand on the results later, but for now here is a quick overview.

Average air flows: Street Dominator 306 cfm, RPM 313 cfm.

Average torque and horsepower 3,000-6,000 rpm: Street Dominator 528.3 lb-ft/454 HP, RPM 532.8 lb-ft/455 HP

Peak Torque and Horsepower: Street Dominator 571 lb-ft @ 4,700 rpm/561 HP @ 6,000 rpm Performer RPM 570 LB-FT @ 4,300 rpm/ 545 HP @ 5,600 rpm