Honestly...how good was the 318...mpg / durability / hp

The original 318 that was in my '70 Duster was poorly maintained over its 115k mile existence before I got the car in 2007 but still ran smooth. Nylon teeth on the cam sprocket all sheared off (as in, every single one) and the valves kissed the pistons when I was pulling out of my high school parking lot. Pulled the heads to find the exhaust valves were badly receded into the seats, some as deep as 1/8" or more. Not knowing any better I threw on some reman'd 302 heads and Performer intake with a 625 cfm Carter AFB and put in a mild Voodoo cam, ran duals off the stock exhaust manifolds. Ran good and sounded great for what it was although it burned a quart of oil a week commuting to college every day 20 miles each way with a trail of blue smoke always behind. My mom even used it occasionally for running errands as it was the only other car we had besides my parents' 2003 Chrysler minivan which my dad needed to commute to work (this was in the late 2000s mind you).

I finally pulled it because it just kept gradually losing power and burning more and more oil. Turned out the rings were gummed up with carbon and the cylinders had huge ridges on the tops but the crank and bearings were in great shape. I saved (and still have) the block and crank, if for no other reason than sentimental value as it was the first car engine I got deep into. I'd love to some day build it into a solid-cammed 7000-rpm screamer or a 349 stroker using the spare 360 crank I have lying around.