Ok I've been reading a few post about there mileage being down on the 360/390 of around 10-12 mpg. Well I have a 302 in my 79 sb with a Edel. 600, headers and dual exhaust. Nothing else, stock rear gear (3.25) stock size tires and no emissionns. I get between 11-12.5 and that's on the highway and I baby it. It's all tuned up, no sticking rear drums so what gives for a measly 302. Why such crapy mileage?

 

I get 20mpg on highway on all stock 302/carby/exhaust in all standard truck, long bed.

 

If you've ripped out EGR, it will account for some mileage loss. Also, a 4-barrel is more efficient in theory, but it does need to be carefully tuned to realize better mileage (not saying you haven't already). Given the factors, it's not surprising to me that people with completely stock trucks are realizing better mileage. Also, "babying it" is really hard to define.

 

My 77 F100 2wd Explorer, 302, 3-speed, 3:00 open rear, headers, was getting 6 and 8 mpg last fall. This spring I installed a new gas tank and rebuilt the 2 barrel carb and just checked my second tank last night and got 9.6 mpg. I have not gotten the carb fine tuned, but everything else is working properly. I'm alittle disappointed with the mileage as well. But 10 is better than 6. I would have expected 12 to 14. But I've been on all short trips, no highway miles.

 

What I mean by baby it is no aggressive starts, no getting into the secondaries. I did however play with the jets in the carb and was loving the extra power but could not afford the fuel loss because it would go fast, so I put everything back to the "economy" setup. And ya the egr has been long gone.

 

I have a 1977 f-100 stepside with a 302, headers, holley 500 cfm 2 barrel, no egr, and I get 23 - 24 highway. The gearing is stock and i am rolling at 3000 rpm at 65 mph. looking to change the ring and pinon to get the revs down to 2500 - 2600 at highway speeds to help with the economy.

 

My truck has the egr and charcoal canister hooked up, but little else for emissions. No PS,PB, or AC options. Going to get some help fine tuning the carb and see. Runs and sounds pretty good as is. Seems it should be doing better the way it's set up.

 

I get 11 around town, 15 or so on the highway. Originally it was 2.75 gears. Now it has 3.50's. There was no change in mileage and the 302 is much happier spinning down the highway than lugging. I have all the emmisions, but have the timing advanced, some slightly larger jets in the 2150, a high flow cat and a Flowmaster.

 

How bad with 4x4

 

Hate to tell ya but the edelbrock is the problem, they have a rich fuel calibration stock.They are designed this way purposely to prevent customers from melting engines due to being to lean.A rich mixture covers a multitude of sins drivability wise. It can be tuned however, there is a lot of info out there about this so I wont give specifics just say mainly get the main metering circuit as lean as possible without lean surge and fatten up the power circuit to compensate under load.

 

A much better carb option would be a 4180 holley as installed by ford on mid to late 80's trucks and cars,It was an emission carb with much more precise fuel metering and economy designed in.

 

My 1972 ford f100 with the 302 and a 3 speed manual gets around 7 to 10 mpg

 

This is gonna be detailed, but I did this for my own purposes, so I thought I would share it with the forum:

1979 F-100 Longbed
302 (D1OE-AA) with 2150 2bbl carb, all stock except for air cleaner
Ported advance, initial timing at 9* to 10* BTDC
19-20 inches of smooth vacuum at 800-850 RPM idle
C6 trans
Dana 44 2.72 rear axle (axle code 11J)
265/75R15 mud and snow tires

Before this test, I re-tuned my carburetor for a snappy off-idle throttle response that I'm very happy with. I am a beginner, but I did a lot of research and took my time to do this the right way (or one of the right ways). So far, my drivability is very good.

Results:
A total of 93.2 km (58 mi) of mixed driving, which included: slow driving on dirt roads, in-town stop and go, about a dozen "hard" pulls to reap the auditory rewards of my snappier throttle, 36 km of highway driving at 80km/h, and 28 km of hauling a full bed of old roofing sheet metal to the recycler, 10-minute idle in the morning.

Used 15.76 L (4.16 gal) of 91 octane.

Total average mileage: 5.9 km/L or 13.9 mpg

Scientific refueling method for super accurate volume count? Listening to when the gas hits the filler neck and the sound changes.

Cheers,

 

Had my 78 for a long time and 2500 mile round trips. Havent checked in years but it had to be in the 15 to 17 range or I wouldn't have been happy. High mph will cut into the numbers. Ford had a check off list for dealers when a customer was unhappy with mpg's. It covered most of the items people would add to their truck. Big mirrors, bug deflectors, running boards, mudflaps, sunvisors, box covers. Almost every add on was a 1 mpg deduction.

 

I like the idea of an MPG score card. Even the box cover? I thought that would benefit your MPGs.