Max MPG- slant vs 318/340

Well I can give you some real numbers as well, but all based on my personal conditions of car, method of driving, etc...

The '79 Dodge St. Regis I used to have had a 318 in it. Automatic, but I can't recall which model. Drove it from about 1991-1993, approx. 60-80k miles on the odometer over that span. It would get about 19-20 MPG at best. Had the electronic ignition, but I don't think it was the "lean burn". Heavy car. It was really slow. I don't know what gears it had but I'm guessing 2:70's.

My '95 Dakota has the 5.2L, with 5 speed trans (5th is OD). 3:55 gears. When I first bought it in 1996, with 18k on the odometer, it would get 16 MPG no matter how hard or light you drove it. The original owner told me that's how it worked for him, and I found it to be true. Enter about 100k+, the motor finally broke in and started giving 18-19 MPG. I did do changes of spark plugs, wires, and general tune-up stuff but not as regular as some of you might. Still driving it today with 247k on it, but it only gets about 14 MPG anymore. Lol. I don't drive it except local, and I mean really short trips, so I know that hurts it. Plus I don't keep up anything for optimal performance anymore. Just fix what breaks to keep it going.

My Scamp w/318/904/2.7X gears I never could give a true MPG on it. I think one time I estimated it to be around 15-16 MPG, but I threw a 4BBL carb on it early on and could never keep my foot out of it when I drive it. Lol.