I have an 85' Dodge D150 truck that is basically stock. I have removed all of the emissions crap and recently replaced all of the vacuum lines and fixed a leaking gas tank and fuel lines. From what I have been able to calculate I am only getting about 13 miles per gallon. Any ideas on how I can improve this? I'm planning on getting my hands on a used carb and rebuilding it because the current one has several leaking seals that i can see fuel leaking from. The leaks are not bad by any means but the side of the carb looks damp but does not feel damp to the touch after i have been driving it.
Thanks for your help.

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1985 Dodge D150

It seems you've answered your own question. My Miser is getting 18 mpg on the highway, so you should be doing a lot better!

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If it was easy, everybody would be doing it.

What is your tire size?
How much air in the tires?
rear end ratio?
What rpms are you turning at 60 mph cruise?
What is your timing set at?
Is the mileage with the truck empty? or pulling a horse trailer?

Fixing the carb will help as well as a good tune up (Bluestreak cap and longer MO-3000 rotor, better plug wires, NGK plugs, HEI, etc.)

My old rig used to range between 16 and 18 mpg with a 4.10 rear end ratio and 32" tall tires.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Is that 13 city, highway, or combined? Because my /6 D-150 would get 13mpg average in the city when I drove it daily. Then again my truck might be in the same boat yours is in . . .

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Get out your aluminum magnets!

Carb rebuild/rebush also go thru distributor and check vacuum advance. Good tune up with good parts. Check exhaust for plugged catalytic converter. Took my Aspen from 17 to 24 mpg hwy in the mountains with heavy throttle foot.

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Thanks Mike

when you removed all the emissions "crap"
1) did that include disableing the EGR
2) what distributor did you change to? or are you still running the OE dizzy?

I have a 1982 D-150 with a Weber 38/38 DGES in it...I swapped out a 32/36 Weber DGES. The reason, I had my foot mashed in the 32/36 and I don't in the 38/38. I get 16 to 18 mpg, driving 60 to 65 mph on the Interstate. I think getting much past the high teens in a truck will take some serious tweaking, and careful attention to how you drive.

That said, this site explains what to do to get you going:

--Remove the lean burn if it is shot
--Replace with a electronic distributor
--Do the HEI ignition swap or go with the stock Chrysler electronic ignition. Many people rave about the HEI. Others note that present day Chrysler ignitions are of shoddy manufacture. I have no problems with my Chrysler electronic ignition (yet) for what its worth. It is the Orange box.
--Get a two barrel intake installed (the extra power obtained this way will, most likely, SAVE you gas)
--Use a Remflex gasket or similar "forgiving" gasket to seal the intake/exhaust manifold
--Install a quality two barrel appropriate for the Slant. I like the Webers, but you need a fuel/air ratio meter to really get them tuned.

A quick surf of this website will help you out. I find that the A-833 O/D transmission is really a pig for making a truck work, like, well, a truck. It is really a 3 speed with an overdrive, and as such it is a long way between gears. With a 3.5ish rear end 1st gear is hardly low enough for truck like duties, and using 4th (i.e. OD) is mostly a wasted effort unless you are on the flat and doing 70 or so. Towing duties almost demand a 3.9 or 4.1 rear end, unless you had lots of money, then you could go with a 4.54 and a Gear Vendors O/D...8 forward gears would be fun I think...

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Slanted D150

Don't forget if the truck is way up in the air your pushing a big
flat box thru the air.
Narrow tires, and close to the ground, and light weight will all help a little.

Of course, if the truck has 4:10 rear gears not much you can do will help.

I had a Chevy Van, small v8, 3:08 rear gears,
I put a Dynomax 3" muffler on it, and ran the exhaust out the side in front of the rear tire, got 18 mpg on the road.With 225/70r15 tires.

All the hints in the previous comments are good ones.

I drove my 81 d150 with that lean burn for years, about 20-21 mpgs at 70 mph, 15-16 city. Not sure of my gears, however it had zero balls after 50 miles per hour, if there was any sort of incline it would require down shifting.

Also, every fill up I would add fuel treatment, basically because I got my gas at an native american reservation, and the gas pumps were older than me.