Gary Lewis Posted September 1, 2020 Share Posted September 1, 2020 I want to run 2 more full tanks at 70 MPH and see what that gets me, last 2 were at 65 MPH as that is what I was doing with out the over drive. Then I will check the timing & and look deeper into the R&S adjustment. Dave ---- When I saw the speeds you are driving, I remembered posting a review of trips to Skiatook, OK over the years and thought I would share: 2014 55-62 mph with no aerodynamic modifications = 21.93 mpg [highest tank = 23.26 mpg] 2015 55-62 mph with aerodynamic modifications = 24.13 mpg [highest tank = 25.72 mpg] 2016 55-70 mph [weighted towards 65-70] with aerodynamic modifications = 22.05 mpg [highest tank = 23.46 mpg] 2017 Missing data due to having driven another vehicle. 2018 65-75 mph [closer to 75] with no aerodynamic modifications] = 19.87 mpg [highest tank = 21.3 mpg] 2019 65-75 mph with aerodynamic modifications = 21.65 mpg [highest tank = 21.95 mpg] 2019 60-75 mph with partial [see explanation, above] aerodynamic modifications = 19.12 mpg [highest tank = 21.17 mpg] I would love to get your lowest of 19 or even mid 17's I could live with. When I am ready to really get into this MPG thing I need to find your post of what was done for timing, carb and aero to get the numbers you did. With the over drive I have been shifting at or just below 2000 RPM and even on the high way in over drive @ 70 MPH it is just at 2000 RPM IIRC, but I have been running 65 MPH because that was what I was running with out the over drive to get a good reading of apples to apples. My gut tells me my main jet (rod & seat) have been played with before I got the truck. The carb was missing screws, had wrong type (sheet metal) screws and had parts in the wrong place. I did not adjust the rod & seat as the paper did not give specs on it so I left it. I don't have the money for a wide band AFR gauge so going to have to wing it but I am guessing if the rod goes deeper into the seat it would be leaner? Some day I will jump into it LOL Thanks for the information Dave ---- Yes, the rod effectively makes the jet smaller, therefore leaner. Link to comment Share on other sites More sharing options...
FuzzFace2 Posted March 11, 2021 Author Share Posted March 11, 2021 Yes, the rod effectively makes the jet smaller, therefore leaner. Little update. I have been driving the truck on & off for sometime now and the over drive works great. The 300 likes to pull at a low RPM so even at 45 MPH I have been using OD. I also lowered the rod into the jet and have run a few tanks since then just have not figured out the MPG yet but I don't think it is much better than before. Today with help from my son we got the air fuel ratio meter installed but have not driven the truck other than to move in from outside my garage into the house garage. It is reading so I guess that is a good thing. I have my monthly eye injection tomorrow and after a little rest I will see about taking the truck out for a spin to see when the AFR is. Before I do that I want to check the timing now that I have a light that should work in day light LOL. I am still getting a little spark knock and need to fix that before something bad happens. Dave ---- Link to comment Share on other sites More sharing options...
grumpin Posted March 12, 2021 Share Posted March 12, 2021 Little update. I have been driving the truck on & off for sometime now and the over drive works great. The 300 likes to pull at a low RPM so even at 45 MPH I have been using OD. I also lowered the rod into the jet and have run a few tanks since then just have not figured out the MPG yet but I don't think it is much better than before. Today with help from my son we got the air fuel ratio meter installed but have not driven the truck other than to move in from outside my garage into the house garage. It is reading so I guess that is a good thing. I have my monthly eye injection tomorrow and after a little rest I will see about taking the truck out for a spin to see when the AFR is. Before I do that I want to check the timing now that I have a light that should work in day light LOL. I am still getting a little spark knock and need to fix that before something bad happens. Dave ---- Nice to have torque down low! Link to comment Share on other sites More sharing options...
FuzzFace2 Posted March 12, 2021 Author Share Posted March 12, 2021 Nice to have torque down low! Yes it is! It may not be fast but it will get the job done and why the 300 was used in larger trucks. Dave ---- Link to comment Share on other sites More sharing options...
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