What Is Good Gas Mileage?

moparlover said
dude the 318 was probably fine with the original heads. by plopping on the 360 heads you probably dropped the compression ratio down to 7:1. that right there killed the mileage. then adding a 4bbl hit it some more. then a duration cam (pumping extra gas/air into the 7:1 compression lol) did it even worse.
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Just to be clear, I did not put this set up on the car. The previous owner had all that work done. I have not even been able to start the car yet because it needs a new starter. Once I get it running, then I can get a feel for how the car runs and proceed from there.