8.5 mpg help

[surfsup]

The carb was rebuilt, . I did change the power valve back to the two stage, one thing I noticed on the one I took out ( the new single stage ) the diaphragm looked distorted, wavy, I know it wasn’t like that when I installed it, so I wonder if the kit I bought was to old and the diaphragm was dried out, as far as vacuum lines go for a possible leak, I have very few under the hood, the vacuum advance and pcv valve to the carb, the egr valve, the brake booster, and I think that’s it. I also replaced the intake gaskets before i installed the motor along with some other things i did. At idle the vacuum gauges reads 17 and it’s steady, no movement at all, at 1500 rpm the gauges reads 19.5 and steady. The car idles at 700 rpm, and seems smooth. Maybe fuel injection is the way to go.