60 mile test at 17.5 mpg = 3.43 gallons of gas added? Kind of a small sample? If the pump at either station shut off easier or harder than the other one, on a small sample it can make a big difference.
For example, if the pump at the second station shut off 1/2 gallon before the pump did when you filled, you would actually have used 3.93 gallons, and got 15.3 mpg. I guess that would still be pretty good. My motor is similar to yours and I get 11 or 12. Try one where you use almost a whole tank some time. The larger the fill up the more accurate the test will be. Mark -----Original Message----- Subject: Re: [Chevelle-list] Whooohooo! 17.5 mpg! Right Clint, although I'm mostly just pretty excited that I can actually drive the car and not break the bank every time. I built the car expecting 10-12mpg tops, and am elated with the 17.5mpg! Here's the specs as others requested: 69 Chevelle (tubbed), ~3800 lbs http://www.prostreetcar.com/69_malibu.html 468 ci, 10.2:1, .625 roller cam, 2.19 intake on 049 oval port heads with bowl blending work only, RPM Air-Gap manifold, 750 Vacc secondary carb (too small), stock cooling system, stock crank, good rods/pistons, K&N air filter, MSD ignition, Hooker comp headers, 2.5" exhaust (too small). Desktop Dyno 2000 software says 550 hp/550 ft/lb, but I'm figuring on 500/500. Trans is a TKO 5sp with .68 OD, 4.33 rear gears with 31" tires (equates to about a 3.73 with 26.5" tires). Runs on 93 octane fuel (Amoco's best). The 17.5mph was a special test drive, averaging 60mph (1900 rpm) for just under 60 miles. I drove very easy, maintained an even speed, no traffic or slow downs. That's useful for determining the ROI on an OD trans, and a best case scenario MPG. Now, when I'm getting on it, my calculations switch to a gallons/per mile equation. :-) Quoting Clint Hooper <[EMAIL PROTECTED]>: > I'm sure one of the reasons Michael posted those numbers is to > illustrate > the effectiveness of a good overdrive tranny. Those are very > impressive > numbers for that car in its present configuration. > My 69 El Camino's mileage went from 16mpg to around 22mpg on the > highway,after I swapped in the 6spd. But,its 350sb is very > mild-mannered. > I'm hoping for at least 15-17mpg with the new 427bb. > Clint Hooper > H&H Custom,owner > LT5 Registry Director > http://www.LT5Registry.net/ > ACES #1650 > http://dalesplace.com/misc/friends/clint_hooper.htm > ----- Original Message ----- > From: <[EMAIL PROTECTED]> > > > > 17.5 is great. What rear gears you pulling? > > > > I don't have a BB but I have a pretty beefy SB w/a 4speed and 3.73 > posi. > I get 6-8-10 depending on you know what! The car is a driver. I > drove up > in driving storm all the way and coming home from a 2 day show in > June after > being rained on all weekend, I was so happy to be going home I just > cruised > all the way. Probably didn't open the 4barrel more than twice over > the > weekend. Total mileage was about 200 and included 140 highway and > the rest > suburban. Very little stop & start til close to home. I filled up > on the > way up and back and kept mileage records. I got over 15mpg. It can > be > done. But it's not much fun driving like that!! > > > > Phil G. 65 SS MCC#36 ACES#555 TC#1766 LGC VCCA AMCA > > >
