<TABLE><TBODY><TR><TD vAlign=top width="100%">I have got to try to do something about my crappy gas milage (7mpg at best). I drive the truck daily around town, never exceeding 45mph. No highway driving, no pulling anything. Currently, I have a stock 2bl and cast iron intake manifold. Is it worth spending the $500+ for an Edelbrock aluminum dual plan intake manifold and 500 4bl carb setup. With smaller primary jets than a 2bl and disiplined driving, in therory, I should yield better mpg, but will it be signficant? I would be ok with 10mpg


Anyone done this B4?

BTW, the truck is tuned properly and has a new tranny. She runs great. Forgot the rear gear ratio, but it is high and ok for my needs.

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Stop an go with 5,400 pounds of iron will eat dinosaurs for breakfast no matter what you change out besides the gain of 3 mpg out of $500 plus will take a long time to recoup.
Your gearing, torque convertor stall will effect mileage.
With that said this is what I would do:
Find a standard iron 4 barrel intake at your local Pick-N-Pull for cheap then add a 570 Holley Street Avenger (Summit) this would help provided you didn't play with opening the secondaries.
I would go thru the dizzy, clean and lube then set it up with a spring kit plus an adjustable vacuum advance unit. Work with it until you have the maximum amount of advance the motor can handle without detonation problems from off idle on up to your maximum rpm limit.
This should get you better mileage.
40 years later these so called new trucks do not get much better mileage around town than old iron and for what $36,000 in plastic cup holders? JMO's.

 

Your fn right about that Beemer I think the 02 Dodge is at about 14-15 in town now if driven very respectible...was about 18-19 and 23 hwy.. new. Stuff rolls down hill dont it ? The F100 did fairly well in comparison last trip from Mojave back to Costa Mesa was about a 1/2 tank driving between 55-70 with only to short busts up to 90.... you just gotta do that.... she begs and begs .... it's like adog without a bone maN!!!

 

What is your rear gear ratio? If it is lower than 3.73 you aren't gonna improve much no matter what you do with the 360. A 390 will out mpg a 360 in most cases when set up the same.

 

Careful Bear, I was going for cheap on this thread vs a 390. Yup a 390 hell 410 will get better mileage yet. For me nothing less than a 410 and gear it tall make it pull, got 15.3 at 64 mph with a C-6 a couple years ago over a 550 mile trip.
Hope no offense taken there Bear.
This would normally be the time of the year I would go to Vancouver B.C. on the motorcycle with summer over and school starting, love that place.
The back says no not the War Department the last 5 years.

 

No offense taken. I mentioned the 390 as not a solution, but as a comparison for how bad the 360 is on mpg.

I know all about living too long after living to close to the edge for away to much. I don't ride anymore since a 1994 incident with a deer, never have gotten completely over it.

 

I would pull the top off that carb check the jet size. rejet it down 2 to 3 sizes Get a K&N air filter. And if you don't have min 2.1/4" duals with some good flowing mufflers.
You can also go to a taller tire like 33", And some guys our going with the 660 4v Q-Jet. There a good milage carb plus good off road to when you get them setup right. Small Primaries for greater mileage & giant Secondaries when your ready to kick it.
Some ideas to kick around our many..Electric fans, headers, Hotter ign system..
Locking hubs. our all things we can do to milk a little more milage out of the FE

My 5,3500+ P/up 11-12 mile. city/freewy my 2cents

 

Side gapping the plugs is good for another mile per gallon helps in the performance dept as well.

 

Actually the cheapest mileage improver as far as spark plugs go is to quit running the ruck plugs with the standard tips and go to the extended tip plugs like the car motors run. Instant improved mileage and plug life and they dont cost any more either. Back in the old days the Champion numbers were F10 or RF10 for the truck motore and the cars ran the F9Y or F11Y or the RF9Y or RF11Y.

 

I have a 66 with a 390 with a 650cfm holley in it and 3:13 gears and I get about 17 mpg hauling a 22 ft car trailer and 3500lbs including trailer. Without the trailer the old truck gets almost 22mpg.

 

Oooooooooook!

 

What the! I guess pigs do fly after all.

 

3.13 gears huh? Never heard of that ratio. A Holley IN it? Try on it and 17 mpg towing, the flag says it all.

 

I too would strip off the two barrel and get a four barrel setup as well. Also an electronic igntion if you don't already have one and while your at it get a multi spark system with a 50,000 volt coil. Also like Beemer Nut said, get an adjustable timing kit to really dial in your total advance. Just adding this igntion stuff gave me an extra 2 mpg alone with my 390. I would also get a set of headers and make sure they dump into some pretty good flowing pipes. I never liked the manifolds on the Fes cause they seemed so restrictive.

 

no 3.13 gears ever made maybe a 3.07 or a 3.25 perhaps or even a 3.00 for a 9 "