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General Site Info => General Discussion => Topic started by: Wadell on December 09, 2022, 11:46:57 AM

Title: 79 k20 5.5 mpg
Post by: Wadell on December 09, 2022, 11:46:57 AM
Hopefully someone can help me I have a 1979k20 truck stock 350 4 speed im getting 5.5 miles per gallon . Is this normal for this truck or is something wrong
Title: Re: 79 k20 5.5 mpg
Post by: bd on December 09, 2022, 05:44:54 PM
The simple answer is that 5.5 MPG seems low.  However, driving style has a HUGH impact on fuel mileage as does maintenance history, gearing, state of tune, condition of the fuel system, the environment in which the vehicle is used (flatland vs hilly terrain), tire size and pressure, vehicle load, the time spent idling the engine vs stop-n-go vs highway usage, and the quality of fuel.  So, the answer to your question is a resounding, "could be normal... could be something wrong..."
Title: Re: 79 k20 5.5 mpg
Post by: JohnnyPopper on December 09, 2022, 07:45:31 PM
Copy that on tire PSI...35 might be a more comfortable ride but it cost you biggly.

I take mine to just under the limit cold.

How many miles are on the motor? If you don't know, I would do a compression test first thing, or while you're doing a tune up.

It can and will tell the tale of your engine condition.

I only touched two of bd's scope, there's a lot more to go.
Title: Re: 79 k20 5.5 mpg
Post by: Big Dee on December 12, 2022, 09:36:12 PM
The brakes might be dragging. lift the front and spin the tire. friction will increase m.p.g.
bd is right in everything written, so pay close attention to that wisdom.
Title: Re: 79 k20 5.5 mpg
Post by: Jimbo302 on December 18, 2022, 06:55:41 PM
For reference, my 77 C20 2wd, 350/th350, 4.10 rear, 31" tires, got 14mpg on the last tank .
Title: Re: 79 k20 5.5 mpg
Post by: Wadell on December 21, 2022, 06:48:49 PM
Thank yall for the wisdom I will look at all of the ideas
Title: Re: 79 k20 5.5 mpg
Post by: Shifty on December 22, 2022, 08:12:56 AM
87 V20 TBI350/400 4.11 gear w/33's, I get 10 smiles/gallon.   :D