15.0 mpg to 21.6 mpg!
It is actually a built 360. The car has no stripes,mags or scoops. Looks like a grandpa's car. 360, 4 speed and a 460 lift cam and 222 duration a .050. 3.23 with 26 inch tire and sure grip. still needs more tire. at about 70 mph at about 3200 rpm getting 16 mpg. around town less, only because my foot is in it all the time.:rolleyes: And a/c blowing cold.
I think your convertor is slipping,lol.
The math says 70 should be 2923 with 26s... 3200 is 9.47% slip.
I suppose your tach could be in error. Or your tires smaller than 26pi=81.7 roll-out.Or your speed-O runs low,lol. Or "about 3200" means 3150 say. The errors are accumulative. For instance a 2% error in the tire roll-out and a 2% error in the tach, and a 4% error in the speedO makes 70.65=3136. Now that would be 7.3% slip from zero, and still in the wrong direction.
So IDK, something seems off. I think you got 3.55s.
The math with 3.55s says 70=3213
Jus saying.
I ran a cam like that with Eddies and 10.9 compression ratio. Also with a double O/D,and 3.55s;70 was about 1700, 895 was 2060. I'd like to tell you that I got 32mpgUS, from point to point on a 10 hr trip to the 2004 Carcraft Nationals in Minneapolis in 2004; but nobody believes that; so you didn't hear it from me. With a Holley 600 even. Of course I modded it; I mod everything; you should see my wife of 40 years, lol.
As to tires it, don't seem to matter much, in a streeter. My 245s went 12.9@106 for the one and only run I ever made with that 223/230/110cam.275s/295s were the same spin-forever deal. Even 325/50-15 DRs have to be babied out.And then they spin. The problem is that cam,lol: it makes too much low-rpm/low-speed torque. But it sure makes mpg! I loved that thing. When it died,I moved up one cam-size to a 230/237/110 and I lost a buncha mpgs. No other changes,at first.
