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Ziegelsteinfaust · 12-21-2012, 12:58 PM

I just got my C20 a couple of weeks ago, and so far have gone from 10 mpg to 15+ mpg highway at 65 mph. Plus after the last of my initial round of mods I hope to sit at 17-18 mpg highway. City I think I am doing 12+ or so. I concern myself with highway mostly as that's where I drive 80% of the time, and 4.11 gears will keep the engine working to hard getting the truck moving.

The previous owner had dual exhaust installed, and it has 9.5x16.5 tires, and the 14 bolt came with 4.11 gears.

I curved and added a HEI distributer, and tuned the Q-jet to the most I can with out a rebuild. I plan to add headers, new exhaust because the old one is shot, and dual electric fans to get the last of the drag off the motor.

My next big mod is to drop in a T200R4 which will sit my rpm at 2200 rpm at 70 mph. I am choosing this trans because its practically a direct replacement for T350 with only new holes needing to be drilled. No drive shaft mods like a T700R4, and its just as strong with a close ratio.

My current 9.5x16.5 tires are some sort of HT tread so I will get 255/60 or 70/17's with highway tread on probably H2 rims.

After all the mods I am hoping for 20mpg highway.

12-21-2012, 12:58 PM	#64
Ziegelsteinfaust Registered User Join Date: Dec 2012 Location: Temple City Posts: 3,666	Re: How Many Miles Per Tank? I just got my C20 a couple of weeks ago, and so far have gone from 10 mpg to 15+ mpg highway at 65 mph. Plus after the last of my initial round of mods I hope to sit at 17-18 mpg highway. City I think I am doing 12+ or so. I concern myself with highway mostly as that's where I drive 80% of the time, and 4.11 gears will keep the engine working to hard getting the truck moving. The previous owner had dual exhaust installed, and it has 9.5x16.5 tires, and the 14 bolt came with 4.11 gears. I curved and added a HEI distributer, and tuned the Q-jet to the most I can with out a rebuild. I plan to add headers, new exhaust because the old one is shot, and dual electric fans to get the last of the drag off the motor. My next big mod is to drop in a T200R4 which will sit my rpm at 2200 rpm at 70 mph. I am choosing this trans because its practically a direct replacement for T350 with only new holes needing to be drilled. No drive shaft mods like a T700R4, and its just as strong with a close ratio. My current 9.5x16.5 tires are some sort of HT tread so I will get 255/60 or 70/17's with highway tread on probably H2 rims. After all the mods I am hoping for 20mpg highway.