[jhv48]

Ok, here are the basics:

Roush 427 SRTW with about 1500 miles on the clock. Street Avenger carb, dual plane Edelbrock intake manifold.

When I pulled the plugs last night, the four on the passenger side were white/very light brown. No blisters or bleaching of the insulators, but slightly darker than new.

The four on the driver's side were all chocolate brown.

The four on the driver's side were all the same color, as were the four on the passenger side.

Why the leaner reading on the passenger side plugs? Wouldn't a dual plane intake distribute the fuel mixture evenly to all 8 cylinders?

Is the passenger side idle mixture screw too lean?

I'm stumped on this one.

No intake manifold leak or carb base leak was found.