I just got a 1979 d-100 with a /6 and a 727. It currently has a 1945 on it, but it needs rebuilt or replaced. I need good mpg as it's going to be my daily driver. I'm wondering if it would be better to replace as opposed to rebuild? This is my first /6. Any help would be awesome!

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Always learning as I go. I've broken a lot of s**t that way.

May want to check these out http://www.daytonaparts.com/
Look at their new replacement carbs.

Dave

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86 Miser 170,000+
2 1/4" exhaust
Holley 1920 #55
HEI MSD BLaster 2
17.8 mpg

I would look for a 1920 Holley Economaster List: R7585.
It will provide the best mileage of the 1920's and 1945's.

There is one on eBay. You can tell by looking down the throat, you will see what looks like a wagon wheel. It provides awesome atomization of the fuel even when its freezing........I love mine!

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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

There is? Where?

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Casually looking for a Clifford hyperpak intake for cheap.

http://www.ebay.com/itm/1973-DODGE-PLYM ... 3c&vxp=mtr

Look on the front view by the fuel bowl vent it says R7585, just like mine.

Here is a 1920 float too!

http://www.ebay.com/itm/Holley-NOS-1920 ... 75&vxp=mtr

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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

Ah, sneaky. More than I want to pay for a carb (especially remanufactured), but someone might jump on that.

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Casually looking for a Clifford hyperpak intake for cheap.

I would knowing what it does for mileage.......
worst case scenario since these carbs are so simple and basically a one piece casting, you could swap out the progressive dual plunger economizer body if it was bad.......the economizer body is the only thing that could go wrong.
It's pretty fool proof!

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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 the 1945 a decent carb? That 1920 is a bit more than what I was looking to spend.

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Always learning as I go. I've broken a lot of s**t that way.

I wish I had known this before I bought 2 1945s.

What kind of mileage difference typically?

The 1945 is a descent carb for about 18 mpg. For the exact same driving (local) the Economaster version of the 1920 Holley gets 22.5 mpg.

On trips over the mountains the 1945 will jump up to 22 mpg.
The same trip the Economaster will get over 25 mpg. On the flat my brick will get up to 27 mpg.

Tests over the last 15 years were with a 1974 1945 with a #58 and a #612 jet.
Tests with the Economaster best mileage results have been with #57 and #56 jets. #57 in the summer and #56 in the winter. On the Economaster both jets provide good punch and spunk so the fun factor is not lost.

At the Pacific Raceways I have run up to a #64 jet for 17.5 to 17.8 sec times, but mileage drops to 20 mpg......

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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

At 4.5mpg more, the carb would pay for itself quick.

Thanks for the info. I'll have to check into the 1920.

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Always learning as I go. I've broken a lot of s**t that way.

It would, but Ted's ride is about 1500-2000 lbs lighter than a Dodge Truck, so mileage on a stock engine with all the right tuning will top out about 18-19 mpg (if it's a manual tranny truck and a short wheel base I've seen up to 21-22 mpg with all the right tuning and not hauling loads)....

-D.Idiot

It's an automatic with a long box.

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Always learning as I go. I've broken a lot of s**t that way.

If you can get 18 mpg with that combination you are doing good. I think the economaster will obviously offer the potential for the best MPG, but there are other areas to focus on first. If you are trying to decide between a 1920 or a 1945 carb, I would consider the condition of the carb and how closely it matches what you have on your truck before being too concerned about grabbing the "better" model. THe 1920 is a very simple and reliable carb. THe 1945 is a smidgen more complex, but still a fine carb.

If MPG is your goal, in other words saving money in operating your truck, I say rebuild the carb you have now (hopefully it is the original carb for your truck) and pay attention to the condition of the throttle shaft housing. If there is any play between the throttle shaft and the housing it passes through, have the throttle shaft rebutted. SPending $300 for a new carb is a big investment. $300 buys at least three tankfuls of gas these days, and that is how much gas you will have to save for the carb to pay for itself in fuel savings.

Once you have rebuilt the carb, the best ways to improve MPG are as follows:

(1) verify that your timing mark is still accurate. The outer ring of the vibration damper where the timing mark is can slip over time, leading to an inaccurate timing mark. The damper in my brother's 1983 van had slipped 8 degrees the last time I checked. You will need a piston stop tool, a flexible tape measure, and some white out to check the timing mark. I (and others) have posted instructions on how to verify the accuracy of the timing mark elsewhere on this site. Do a search for it.

(2) disassemble, clean, and rebuild your distributor. What you want to do is be sure that the mechanical and vacuum advance mechanisms are working properly. Make sure the mechanical advance weights and the reflector plate in the distributor are lubed and moving freely. Make sure the vacuum advance pod still holds a vacuum.

(3) verify that the vacuum advance pod vacuum hose is connected to the correct port on the carb. You want a port that has vacuum only when the throttle is opened.

(4) do a thorough valve adjustment. I prefer .012 intake and .022 exhaust valve lash for a little more low RPM torque. Low RPM torque will help your big heavy truck get moving. Valve adjustment is discussed here: http://www.slantsix.org/forum/viewtopic ... ght=#72139

(5) do a good tune-up. New cap, rotor, spark plugs, filters (oil, air, PCV). Run a the correct heat range thermostat and 5W-30 oil. Whatever you do, stay far away from Fram brand products.

(6) make sure the bands in your auto transmission are adjusted properly. Also make sure the kick down linkage is adjusted correctly.

(7) make sure your tires are inflated to the correct pressure.

(8) Rig up a true cold air intake for the air cleaner. This doesn't have to be anything fancy, just a length of dryer hose zip-tied to the end of the snorkel with the open end fastened behind the grille or somewhere it will draw fresh air.

(9) make absolutely sure the thermostatic choke system is adjusted properly, including the electric assist. Better yet, replace the stock thermostatic choke coil with the all electric one sold by CarbsOnly. Again, search the site for more info.

Once you have these basics covered, then you can start trying things like recurving the distributor (discussed in a sticky under the FAQ in the engine section) and playing with fine tuning the carb (jets, etc…).

If you get all these things done, Your truck should be getting at least in the mid teens if not high teens MPG. Then you can start playing with things like body aerodynamics, camshaft selections, milling the head or block for more compression, changing the carburetor, etc….

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Casually looking for a Clifford hyperpak intake for cheap.