318 Gas mileage?
Too big for MPG with 2.76 gears, your not making enough vacuum, I bet.
Holley thing too.......
The SP2P should do better than a performer, the best MPG manifold is the Offey dual port tho. I had a magnum, with a 440, with 2.7something gears, it got about 22 HWY with a smooth idling 440, the same car with a 318 I bet would have gotten 14. Gotta lower the gears with the smaller motors.
I had a 69 D200 getting over 20 on the highway, for a box, with 31-12.50's on the back, I thought it was pretty good.
It was a 318, 727, 3.55 D60, Dual port, EB600, stock points igntion, 252 comp cam, decked block, port matched, and I tuned the carb with a O2 sensor.
Sometimes mileage just needs some tuning.
And as said before, lean is worse than rich, I had a friend who thought he was a mechanic, and was running a ol 625afb on his 318, he leaned it to the point it had a lean miss inless it was under slight acceleration........
7mpg at best. LOL
