[mr0077]

Mike, my stock Ford manifold has about 9 degrees of incline (down in front) relative to the engine. I never had a problem with my 390 CFM carbs, but when I changed to 600 CFM carbs it flooded and stumbled on moderate to heavy braking. I figured it was because of the carb tilt, so I lowered the primary float levels about a turn or so and it eliminated the problem. It was so steep that when I tried some of the old (BK/BJ?) style carbs with the fuel balance tube between the front and rear bowls, gas would run out of the front (secondary) sight plug when the rear (primary) fuel level was brought to the bottom of the sight plug.

Anyway, on your problem, if you're thinking of swapping manifolds, maybe you should have the carb pads on yours milleddown and more level...measure the angle of the engine from level on level ground (which is the same as the ports on the manifold) and how much you need the carbs lowered, and see if you can get a wedge milled off so it both lowers and levels out the carbs. I have heard of people doing that, but don't know/haven't heard whether it has any performance effect.

FWIW, if you change to paper elements (better filtration and cheaper than K&N but more restrictive), you will have about a 6-7 HP loss compared to no filter at all (based on my dyno results on a 427 putting out 400 HP at the wheels)...to me, that is not restrictive.