The Situation
We are currently in the process of building a 505-inch big-block using a set of Indy EZ heads and the new Mopar Performance cross-ram intake. While we were waiting for some custom parts to be finished, we decided it would be a good idea to toss the cross-ram onto the flow bench and see how well it would-or wouldn't-do. The results had us scratching our heads, so we unboxed a pile of big-block manifolds we had sitting on the shelf and tested several combinations. When the dust settled, we had just about wore out our wrenches by testing twelve different intake manifolds, but we also learned a thing or two that you might find interesting.

Indy EZ heads
All the tests were run with the intake manifolds bolted to one of our new Indy EZ heads. These relatively new heads from Indy Cylinder Head are the answer for engine builders who want to make some serious power while keeping the exhaust ports in the factory location. While most aftermarket heads have the exhaust ports raised for better flow, the guys at Indy figured out how to get a decent exhaust port into a stock location on these heads. These EZ heads can be ordered in several different configurations from Indy, including a standard port version and three different versions that have Max Wedge-size intake ports.

Our heads came from Indy in the standard port configuration, but after some dyno testing last year we sent them off to be CNC ported by Jeff Kobyiski at Modern Cylinder Head (MCH). Jeff is fairly well-known in SS/AA circles as the guy who makes Hemi heads really flow, but he also has CNC porting programs for various wedge heads, including the Indy and Edelbrock parts. The CNC program that Modern Cylinder Head uses for the EZ heads resulted in a finished intake volume of 308 cc and a maximum flow of 351 cfm at .700-inch lift.