5-10 hp isn't enough to say there's a difference, especially if you found that after porting it.. You can do that just by switching carbs.
The runners are definitely less pronounced in the O.E. manifold, and maybe my inexperienced eyes are playing tricks on me, but also look shorter compared to the Edelbrock. Reason I ask is because I have an Edelbrock 2121 and figured since I'm going with a 331, I should have gotten an RPM Air Gap.
I get a little annoyed when people say that the Performer is the same as the O.E. 4V intake except aluminum. They are not the same. Period. Is it a radical difference? No. But they are not the same, and the performer is slightly taller.
I get annoyed when people think the Performer is something better than the stock intake. There's not enough difference there to justify buying a new one vs a $50 stock intake. If you're going to buy new, buy the RPM. There's virtually no difference on the bottomend between the Performer and the RPM, so you may as well get your money's worth and skip the Performer.
Well, I for one, am not one of those people. I've never said the Performer produces more power, however the weight savings is an advantage, so in that respect, it is better.
