[Cliff R]

Dave will port your intake, he uses a CNC scan of my intake.

On the dyno on a 440CID engine my intake made 497hp. Switching to an Edelbrock Performer RPM dropped to 491hp. Swapped on one of those HO reproduction intakes next and made 487hp.

Average power was best with the modified iron intake as well. I suppose the larger RPM may have a "crossover" point someplace where it starts to make more power than my modified iron intake.

I ran an RPM intake for a while on my current 455 and HATED it. Took some "cobbling" to get it under the hood, which included raising the throttle cable bracket, going to a 1" shorter Shaker and not being able to use a stock type air filter in it. Moving the lid 1" closer to the carb KILLED engine power and I couldn't even make a full drag strip pass with a lid on the air filter!

I ended up making a custom filter for the Shaker opening. Ran that set-up for a while then bought a real HO intake that Dave at SD CNC ported for me and modified with my CNC scan.

It allowed me to go back to all the factory air cleaner parts and guess what, it runs QUICKER in 60' times than the RPM intake! It gives up about 1mph on top end, but that's nothing compared to all the cobbling and drama required to fit an RPM intake under the hood on one of these cars.....FWIW.......