How does this sound for gas mileage?

[K5_Fla]

I never have figured out how much MPG my K5 is getting until this weekend. Speedo is not connected so odometer doesn’t work… probably wouldn’t be close to accurate anyway because of big tires.

So…. I filled it up to the very, very top. Drove exactly 100 miles to my destination ( I know it’s exactly 100 miles because I drive it a few times a month in my other truck) The total trip is 95 miles of full highway speed….

My truck - carb 350, edelbrock carb and intake – everything else stock. 35 in tires, 3.73 gears, turbo 350 trans. I only run the truck up to 2300-2400 on the highway at about 62-65mph (GPS)

When I got there I filled it back up and divided the gallons by the miles driven. Came up with 12 MPG – which I thought was pretty good. Sound about normal ?

 

[scottsdale86]

Sounds a little generous to be honest. Edelbrock carbs are't know to be very good with economy. I get that with a well tuned quadrajet and newer 260hp crate engine with everything else stock except edelbrock SMOG legal headers and magnaflow cat and exhaust. Probably closer to 10mpg in your case. but you would have to empty the tank completely then refill it with an exact amount then drain whats left when u get there and see whats left to get a exact figure. With these things i dont worry about mpg. I have a Scion tC for that stuff. But i havent driven it in over 4 months so i prefer to drive the truck.

 

[K5_Fla]

Yes – I thought it would be closer to 10 mpg….. was surprised. But the truck is tuned perfect in every way. Engine has some miles – but plugs, wires, cap, etc, etc, etc… are brand new. Replaced a tons of parts recently.

 

[FastMaxx]

12 mpg with a setup like that sounds pretty normal to me?
A good running 350 is not that bad on gas. The load on the engine (weight of the truck and the air drag going down the road) is one of the major sources of fuel consumption.

 

[blazinzuk]

The fact that you are in Florida and the truck is tuned nicely I would say 12 is reasonable.

I bet if you bumped it up to 75 it would drop to 10 or even lower.

On one of my trucks every 10 mph from 55 on up pretty much equated to a 1 mpg loss

 

[K5_Fla]

your right... but at 75 mph my truck would blow sky high! lol... feels bad enough at 65 mph with the 35 swampers...

 

[big dan]

I have nearly the same setup, 3.73s and 35s with a th350 but I run a q-jet on a mild 350 and can get between 12-13 at 60mph or less. Once I hit 70 Im pretty sure it drops to the single digits though.

Ive never noticed any problems with edelbrocks having poor mileage. Ive had two of them on this same truck and mileage was about the same.

 

[noJeepshere]

My Jimmy, that I had, when it actually ran, got anywheres from 9-13, depending on what I was doing. That was with an old 350, Edelbrock carb, sm465, 3.73 gears and 31" tires running at 60 mph most of the time.

 

[buffblazer]

your right... but at 75 mph my truck would blow sky high! lol... feels bad enough at 65 mph with the 35 swampers...

nah 350's will turn 4k all day long, mine has 4.56 gears, 35's and a SM465 and i turn about 2900 at 65 3300 at 75. runs great and sounds good.

 

[USSkoval]

I seem to get 12 or 13 out of my '77. Mild 350 with 750 Holley, th350, 33's and 3.08's. So that sounds about right.

 

[trustyrusty]

Anyone know if the newer (91) k5's with fuel inj. do much better?
I would check mine but the speedo is off (running 32;s) and I cannot afford to fill the tank.

 

[smier]

'91 blazer stock except for a flowmaster catback on 31's... I drive aprox. 40 miles a day, I've Been averaging 16+ mpg with a high of 18 mpg when I took it for a good ride on the highway. This week should be my worst, I idled almost 3 hours and had to make some of trips to the yard in 4x, so I'm pretty sure it's going to be bad... I've replaced just about every sensor, rebuilt the throttle body, all new plugs, wires, cap, rotor, etc.... Wasn't cheap, but before I did all that I was only getting 12 mpg!!! Getting ready to put a k&n filter, a high flow cat, and contemplating doing the ultimate TBI mods from thirdgen.org next. There are guys that have claimed 20 mpg on the highway, I used to think they were full of it, but I'm starting to think I might be able to do it. I have to tell you I worked at the 18 mpg, I drive tractor trailers for a living, and you get pretty good at conserving fuel when it costs almost a grand to fill up...

 

[smier]

Well, the truth hurts, I just filled up this morning after thinking about this all last night and mine took 17.61 gallons and I drove 194 miles so far this week in the snow and ice for an average of 11.016 mpg. This is my worst in a long time, but I had to idle almost 3 hours to melt all the snow tuesday and a 1/2" of ice off yesterday, and a couple of those trips were in 4 wheel drive... I've been averaging 16 mpg consistently even on the winterblend of fuels. I run super constantly because my truck does not like 87 octane. As suggested before, a good way to check your odometer and speedometer is with a gps unit. Mine is only accurate from about 30 mph until I get up to about 75 mph.