340 block stroked & bored to 418. I will be running a Quadrajet spread bore carb. My 2 choices are basically the Weiand 8007 or an Edelbrock Performer. The Performer is just a regular Performer, not the RPM version. Edelbrock apparently does not make a spread bore Performer RPM for our small block motors (WHY?!?!)

So my question is this - is the Weiand 8007 any good? Will it outperform the Performer? This is for a daily driver street car that sees the strip about 12 times a year.

Why not a M1 it's set up for a spreadbore?

Weiand 8007 for sure.

Make sure you gasket match the runner exits. The roof necks down to 318 size for the last inch or so. That needs to be corrected.

on a 408, I'd look for a used LD340 to modify, or use the M1 single plane. the bigger motor will appreciate the increased plenum volume of a single plane, and the displacement will offset any torque loss due to the single plane.

mod a LD340 to take a spredbore carb

well worth the time and effort,IMHO

LD340 is right on par with the eddy airgap rpm intake even though its 35-40 yrs old

its duel plane also

The RPM isn't the best street driver manifold. The LD340 is a acceptable unit.

If thats all you have , go Weiand, more upper end torque through 5000rpms. The performer will work just as well, but Choking the motor out at 5k. Add a spacer cause, Another 500 rpms means the world.