408 Stroker Build / Intake Question

Edelbrock started advertising the small block Magnum Air Gap several months before they ever made any available in the marketplace.

I lusted after one for over 6 months, and was told that casting problems were holding up production (per the Edelbrock office.). I was frustrated, because it seemed like a great manifold, for a street/strip car, like I was trying to build. I hate buying foreign-made parts.

But, I really needed a manifold, and the Professional Products manifold was available, so I bought one. Turns out, it's not really a carbon copy of an Air Gap, but, close... My engine is supercharged (Vortech), so if there are any actual flow differences between the two, the blower would probably make it hard to tell.

When I got the manifold, I placed a MoPar factory intake gasket on the mating surface, and the port-alignment looked okay to me. There were no places where it looked like it was even close to the edge of the port, so, I used it without any grinding at all, anywhere.


My only problem was that I am using a 750 Holley 4150 double pumper, with float bowl extensions, and I ran into clearance problems on the back, left (passenger) side of the carb where the rear accelerator pump needs clearance to work when the throttle is opened. Professional Products could have placed the vacuum fitting hole in the manifold farther from the carb base, and it would have alleviated that problem, entirely. As it was, I had to grind away a lot of the fitting to get it to clear the accelerator pump arm.

I couldn't raise the carb with a spacer, to deal with that problem, because of hood-closing issues (no hood scoop.)

I've run this manifold for about a year, now, and have had no problems of any kind, with up to 10 pounds of boost and several drag strip runs. My 360 Magnum with a nearly stock short block, made 445 RWHP and 470 RW torque on a DynoJet chassis dyno with av gas and 10 pounds of boost, in case anyone was curious about how the manifold worked. Nearly stock Magnum heads.

So far, I'm happy with it, but I was thinking about replacing it (for "political" reasons) with an Edelbrock Air Gap in a couple of years, but now, I'm gun-shy; those photos are scary....:angry7: