SBM Edelbrock SP2P

Hate to muck up the "Wanted" thread but @Rug_Tucker is right. I had one of those and the ports are like 1" by 2"! (j/k) They are so tiny I thought there would be some serious reversion and pooling of droplets where the intake meets the head. These were designed with small runners to get velocity up.
Look downstream to the heads. When these came out it was a reaction to the times, and what were the heads they had? Crappy.
An intake isn't going to give you economy. The wrong one can take it away though. Sounds illogical but I believe the economy is in the heads and the valvetrain (cam), as far as the engine goes. Of coarse an overdrive trans helps economy too.
You need to have your heads built like a performance build as far as the approach, light clean up and a good valve job. Use a good dual plane (not SP2P!). It's all about OPTIMIZING the engine. What is optimal for the best economy? I would use a cam in the 214-220 @.050 range and a 2.76:1 gear with a 3 speed or 2.91 or 3.23 with an OD.
Don't build economy around an intake manifold, especially the wrong one. SP2P belongs on the wall.