[Cliff R]

"He reported with the Edelbrock Performer intake manifold on his car there was no change in ET or MPH. That said, we both know different engine/vehicle combinations can and do reflect different results."

Steve, I'm sure that at that time Jim was able to run equally as well with either one.

So take that information plus the testing I did with it on a more powerful engine with aftermarket aluminum heads and somewhere in between that intake gets very restrictive on a 455 build.

I was NOT able to use it for track testing as it failed street testing miserably. When you go to full throttle and get a HUGE stumble, then "surging" in the mid-range, and the ONLY part you've changes was the intake, well, common sense says to remove that part as it's NOT going to work well for what you are doing. Also keep in mind that I also tested a truckload of other intakes and NONE of them caused any issues anyplace with hesitation, stumble, bog or surging at WOT.

I can tell anyone reading this that IF you are limited to the height of the stock intake and your engine is at or past about the 450hp mark, the best intake for your engine is goind to be the stock cast iron or aluminum HO. ALL of the other intakes I tested except for the RPM (it's already over 1" taller than a stock one) REQUIRED a 1" spacer to work well.

I found the same thing on the dyno. At least a 1" spacer is required for all the single plane intakes available for these engines or you are leaving some power on the table. The higher level of power your engine is, the more it will benefit from a well blended 1" spacer on ALL single plane intakes.

The Performer RPM really doesn't need one and it really becomes a PITA to add one for most of these set-ups, especially if you are trying to get it all under the hood (without a HUGE hole in it) or use factory Shaker or Ram Air parts.......FWIW.......