My 340 getting 6 mpg

This is just a consideration, Stop n go so. Cal traffic is a terrible way to average hwy mileage.
On average it takes 1.5 hrs to drive 68 miles at off n on 80mph in stop n go traffic. My impreza 4 banger shows 6.5 -9 mpg when accelerating to speed. ..then it's 29-37 mpg at cruise. Dbl pump 340 with a cam is going to see less.
Just food for thought.
That carb isn't right and imo is main problem. I didn't build this motor, but ime my motors don't need break in time to make decent fuel mileage. Things do not get or are not that tight from a re build.
Driving style, carb, tune , open headers...those will hurt the mpg.

I love when people who aren't well versed speculate...then latch onto one detail they do understand and start pushing back with it. Get the fkn carburetor changed then comment. You don't need a dyno tune...unless you can't read a book n tune a carburetor or get me to come up that day. This combo isn't tricky to tune, Trust me.Tried cranking comp test but the gauge he has pissed the squeeze out. Junk. It DID push into the 150's before spinning back down 'old snap on' . The motor , if it had any sealing issues, would not pull or perform very well if it did...would be popping ex and coughing if the valves weren't sealing... it would push oil out the dip stick tube and breathers if the rings weren't sealing.


It's the carburetor.