MPG...? Round about Est.

jayman2003

jayman2003

Member
I've got a 77 Scout II with the 345 v8, Holley 2 barrel carb, auto tranny, a small lift (2.5 inch), and 32 inch all terrian tires. Otherwise it's pretty much stock. When I bought the truck the timing was advanced way ahead to compensate for a vacum leak and plugs that were about as black as coal. So new plugs, timing, and carb tuning later. It starts, runs, ans stops just fine...but I don't think it's running quite right and I will be finishing the rest of the tune up this weekend (rotor, cap, and wires).

So knowing all that my question is I'm getting a whopping 7 mpg...what is the "normal" mpg for a properly tuned pretty stock Scout II with the 345
 
I have a 72 piclkup with the same cmobo with the exception of the lift and tires, and I get 9-10 mpg
 
Well thanks...I keep finding info online from people that say they have gotten 12-13 mpg...but I don't know if that is really true.
 
jayman2003 said:
I've got a 77 Scout II with the 345 v8, Holley 2 barrel carb, auto tranny, a small lift (2.5 inch), and 32 inch all terrian tires. Otherwise it's pretty much stock. When I bought the truck the timing was advanced way ahead to compensate for a vacum leak and plugs that were about as black as coal. So new plugs, timing, and carb tuning later. It starts, runs, ans stops just fine...but I don't think it's running quite right and I will be finishing the rest of the tune up this weekend (rotor, cap, and wires).

So knowing all that my question is I'm getting a whopping 7 mpg...what is the "normal" mpg for a properly tuned pretty stock Scout II with the 345
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A Scout II has the aerodynamics of two sheets of plywood standing on end. And...they are much heavier than any comparable vehicle of that era. Those two factors add up to a typical milage figure of 12>14mpg at cruise speed in an extremely well-tuned state, unloaded.

Outstanding milage for tuned pickall will be in the 10>12mpg range unloaded.

Ya don't operate these rigs with any expectation of fuel economy of any significance. These are heavy dam rigs, based upon a platform designed in the late 60's of the last century. These are truck motors, not chryfordrolets. Fuel efficiency was never a consideration when they were current, nobody cared!

We run 'em now because they are one of the most politically incorrect statements you can make motor vehicle-wise...they are the perfect piece of carbon-belching machinery for pissin' on greenies and treehuggers.
 
michael mayben said:
a Scout II has the aerodynamics of two sheets of plywood standing on end. And...they are much heavier than any comparable vehicle of that era. Those two factors add up to a typical milage figure of 12>14mpg at cruise speed in an extremely well-tuned state, unloaded.

Outstanding milage for tuned pickall will be in the 10>12mpg range unloaded.

Ya don't operate these rigs with any expectation of fuel economy of any significance. These are heavy dam rigs, based upon a platform designed in the late 60's of the last century. These are truck motors, not chryfordrolets. Fuel efficiency was never a consideration when they were current, nobody cared!

We run 'em now because they are one of the most politically incorrect statements you can make motor vehicle-wise...they are the perfect piece of carbon-belching machinery for pissin' on greenies and treehuggers.
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I understand the common sense of my situation (weight, gears, driving a brick down the road, the fact that my Scout isn't used as a "commuting" rig)...but we don't have any other Scout owners around here to ask. I have found info on the net but I would like the info from "actual" Scout owners...
 
If I can keep my foot off the floor, I can get 14mph hwy with regular gas not ethenal.
Same specs as yours only 31" tires
ron
 
ronmc1954 said:
if I can keep my foot off the floor, I can get 14mph hwy with regular gas not ethenal.
Same specs as yours only 31" tires
ron
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Thanks man...I think I need to finish the tune up and do some more tuning. Make sure I'm setting the timing when it's hot not just warmed up, while I'm talkin about it does anyone know weather or not I need to unhook the vacum line from the distributer when setting the timing or not? :icon_confused:
 
With my 345 4sp 3.73 gears and 235 tires, pretty much as stock as you can get, that I do use for my commuter I get around 11-12 mpg. That is a commute that is heavy on "city" driving and a couple of stop lights that I have to sit at for 2 or sometimes 3 cycles to make it through.

The worst I've gotten was about 10 mpg and that was with a lot of idling jump starting another vehicle that had a totally dead battery so it was sitting running at a forced high idle for 15-20 minutes.

So yes 7 mpg seems low and you should be able to improve that, unless that 7 mpg was while wheeling particularly if using low range.
 
eric vanburen said:
with my 345 4sp 3.73 gears and 235 tires, pretty much as stock as you can get, that I do use for my commuter I get around 11-12 mpg. That is a commute that is heavy on "city" driving and a couple of stop lights that I have to sit at for 2 or sometimes 3 cycles to make it through.

The worst I've gotten was about 10 mpg and that was with a lot of idling jump starting another vehicle that had a totally dead battery so it was sitting running at a forced high idle for 15-20 minutes.

So yes 7 mpg seems low and you should be able to improve that, unless that 7 mpg was while wheeling particularly if using low range.
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No wheeling just normal driving around town...and a few jumps on the freeway for about 10 min each time.
 
If this rig does not have to be smogged, then review this sticky for a process for ignition timing for best performance (which equates to best fuel economy):

http://www.forums.IHPartsAmerica.com/ignition-tech/2122-ignition-power-timing.html

If the engine and all sub-systems are virgin, and all emissions devices are in place and functional, there is no need to disable the vacuum line to the distributor if your ported vacuum source at idle reads <5"hg. If a reading is greater than 5"hg, then you have some tuning issues to work out.

The ignition system must be completely dialed-in and locked down before making any adjustments to the carburetor.
 
michael mayben said:
if this rig does not have to be smogged, then review this sticky for a process for ignition timing for best performance (which equates to best fuel economy):

http://www.forums.IHPartsAmerica.com/ignition-tech/2122-ignition-power-timing.html

If the engine and all sub-systems are virgin, and all emissions devices are in place and functional, there is no need to disable the vacuum line to the distributor if your ported vacuum source at idle reads <5"hg. If a reading is greater than 5"hg, then you have some tuning issues to work out.

The ignition system must be completely dialed-in and locked down before making any adjustments to the carburetor.
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Thank you for the information, and thank you for doing the leg work to find the resorces. I appreciate the help:icon_up:
 
I don't believe I have points, and there was a guy out at my house the other day that is a self proclaimed "Scout enthusiest" who said that someone had upgraded my distributor and I no longer used the "gold box" with what I had...

Does anyone know what he was talkin about...? :icon_confused:
 
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Thier are 2 different types of distributors. You have electronic and points. Points have a condenser and a "gold box" as you call it and the electronic is much better as it is semi compter conrolled? If im off im sure some one else will point us in the right direction
 
jayman2003 said:
I don't believe I have points, and there was a guy out at my house the other day that is a self proclaimed "Scout enthusiest" who said that someone had upgraded my distributor and I no longer used the "gold box" with what I had...

Does anyone know what he was talkin about...? :icon_confused:
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We have a tremendous knowledge base regarding ignition systems in this sub-forum, including a distributor identification thread:

http://www.forums.IHPartsAmerica.com/ignition-tech/

Likewise regarding carburetion. Ya might spend some time cruising threads in those areas.
 
Another hing to consider is the accuracy of your speedo. Switching from the stock ~29" tires to a 32" tire means that you are traveling roughly 10% further than the speedo would indicate.

Hop out on I-5 and check it against the milemarker posts. Not the most accurate but it will get you in the ballpark.
 
eric vanburen said:
another hing to consider is the accuracy of your speedo. Switching from the stock ~29" tires to a 32" tire means that you are traveling roughly 10% further than the speedo would indicate.

Hop out on I-5 and check it against the milemarker posts. Not the most accurate but it will get you in the ballpark.
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Yeah I'm about 5 mph off at freeway speeds.
 
Thanks to everyone for all your help. Even more so since this has become a general discussion rather than the title ;-)
 
I've got a '71 1210 2wd 304 that averages 10-14 mpg. I was actually surprised it was that high. That truck is effin' heavy. I don't know how accurate my speedo and odometer are so I went the usa track and field site on the internet. I filled up my truck and took it on a 50 or 60 mile journey, filled it up and figured how much gas I used. I then went to the usa tack and field site and made my own run route of the exact route I took while driving around. A little tedious, but it was a mix of highway and city driving and it proved to be very acurate.
 
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