Lets make the best real world *MPG* THREAD EVER !!

Without writing a novel...

Best I ever got out of my built slant- cam, head, bigger carb, header 3.55/2600 stall was about 21-23mpg in a 71 dart swinger fully loaded. I thought that was decent.
Nothing I do focuses on more milage per gallon...its only a byproduct of good combo and precise tuning. They've all gotten better milage than typical and or expected.
I dont use vac advance on my stuff.
I do have an adjustable timing box I'm hooking up that I can carefully dial in another 6-10 degrees at cruise.
See when you build something that's really ragged Edge compression and octane that just squeezes by when you hook up that Advanced can which is operated on vacuum the vacuum does not change fast enough to pull the timing back out once you stomp on it and in every case with engines I do that I mean are literally on the edge of being able to run on high octane pump gas it just doesn't work they ping every time momentarily.
By the time I take enough out of the can to make it stop... its only adding around 6-8 degrees. I bought an msd pro billet and halted investing my time or motor into vac advance at this level.
All my mopars got better milage than any Chevy built the same. Chevy sucks.