Some people have had good success with them, a few have had issues. But then again, a few people have had issues with the Eddy’s too. Quality control isn’t what it used to be.
I think the trick is to buy them through a retailer like Jegs or Summit. At least that way if you have an issue you have a decent return/replacement policy to fall back on.
Yeah that’s how they get away with it, although I’d be surprised is Edelbrock doesn’t still have an argument since they’re so darn close. I mean, they look exactly like AirGap manifolds other than the extra set of mounting bosses for the magnums.
The problem with proving they’re all the same casting is I think that you’d literally need to buy a bunch of them, one from each of the brands/companies marketing them, and compare them side by side. Based on the pictures I’ve seen they all look the same. I think it would take more than just a casual comparison to show the castings are actually the same, and I don’t know that you’re gonna find someone to buy several different intakes and evaluate them all. Especially since some of the brands would probably need to be bought from retailers that might have less than spectacular customer service.