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 Post subject: Mileage Question
PostPosted: Tue Apr 12, 2011 11:06 am 
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1 BBL (New)

Joined: Tue Apr 12, 2011 10:33 am
Posts: 4
Location: The Desert
Car Model:
Howdy everybody! Not only am I new to this Forum, but I'm new to Mopar's as well. I recently acquired a '66 Valiant more-door with a 225 and a 904. The car had sat for a long time (the car still had bias ply tires on it!) and needed ALOT of work to get her road worthy again. I've been driving it daily now for a couple of months. Anyways, here's my question... I rebuilt the single barrel Holley on it in hopes of getting some better mileage. While the car does run a whole lot better now, I'm still only getting about 10.5 mpg (?!). And that's driving around town and doin about 60-65 mph on the freeway. That works out about to about 190 miles per tank. No bueno. Did I mess up the rebuild? Could the motor be tired? Could it just be the way the car is geared? How can I identify the ratio? Any ideas? Suggestions? Like I said, I'm new to Chysler products (I grew up with GM stuff) so any and all help would be appreciated. I'm hoping you guys have some "slanted" tricks up your sleeves! Thanks in advance :)

bob_o

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 Post subject:
PostPosted: Tue Apr 12, 2011 11:14 am 
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Guru
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Joined: Mon Oct 14, 2002 4:32 pm
Posts: 4880
Location: Working in Silicon Valley, USA
Car Model:
Confirm some other things before going further with the carb.
- Is the distributor's mechanical and vacuum advance working correctly?
- Is the valve lash set to specs? (.010 on the intake valves, .020 on the Exhaust)
- Do you know the cranking engine compression in psi?
DD


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 Post subject:
PostPosted: Tue Apr 12, 2011 12:26 pm 
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1 BBL (New)

Joined: Tue Apr 12, 2011 10:33 am
Posts: 4
Location: The Desert
Car Model:
Awesome, thanks Doc. I'll start checking into those suggestions!

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 Post subject:
PostPosted: Tue Apr 12, 2011 5:03 pm 
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2 BBL ''SuperSix''

Joined: Sun Apr 03, 2011 7:56 pm
Posts: 22
Location: New Zealand
Car Model:
Hey bob-o,

Have a go using the search function at the top of the board for terms like 'MPG' or 'fuel economy'. There's a wealth of info on how to get that 190 miles per tank to over 400.


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 Post subject:
PostPosted: Wed Apr 13, 2011 8:20 am 
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1 BBL (New)

Joined: Tue Apr 12, 2011 10:33 am
Posts: 4
Location: The Desert
Car Model:
I'll do that Duke. Thanks man :)

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 Post subject:
PostPosted: Wed Apr 13, 2011 8:20 am 
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Turbo EFI
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Joined: Thu Nov 11, 2004 4:33 pm
Posts: 1004
Location: Sacramento, CA
Car Model:
This is a good link to get started on

http://www.slantsix.org/forum/viewtopic ... ht=#138010


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 Post subject:
PostPosted: Wed Apr 13, 2011 9:11 am 
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Board Sponsor & Contributor

Joined: Thu Oct 31, 2002 5:39 pm
Posts: 24805
Location: North America
Car Model:
Tune-up parts and technique suggestions in this thread. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. Make sure your 1920's power valve hasn't fallen apart (see here).

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 Post subject:
PostPosted: Wed Apr 13, 2011 3:38 pm 
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2 BBL ''SuperSix''

Joined: Sun Apr 03, 2011 7:56 pm
Posts: 22
Location: New Zealand
Car Model:
.... and are you still running a points distributor?

Easy GM 'HEI' mod to electronic ignition is recommended.

Again, just search for HEI and you'll find what you need. 8)


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 Post subject:
PostPosted: Thu Apr 14, 2011 8:45 am 
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1 BBL (New)

Joined: Tue Apr 12, 2011 10:33 am
Posts: 4
Location: The Desert
Car Model:
I've made a list of all the suggestions you guys have given me, and I'm gonna start goin through them this weekend :)

Duke, the car still has a points-type distributor in it. I was actually thinkin about tryin to locate an HEI for it, so thanks for that!

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 Post subject:
PostPosted: Thu Apr 14, 2011 1:35 pm 
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Supercharged
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Joined: Sat Feb 16, 2008 1:25 pm
Posts: 5613
Location: Downeast Maine
Car Model:
Before spending a wad of dough, make a quick check of the point’s gap. If the engine runs well after adjusting, you have found the problem.

Where your car sat for a long time, the points could just be corroded, or closed up a bit. File or clean, and reset them. Don’t forget to put a little Vaseline on the six sided cam that opens & closed the points. If left un-lubed your points will fall out of adjustment rather quickly from wear.

We are spoiled these days with electronic ignition equipped autos. Before those orange boxes became the norm, one had to inspect their points ignition about every 6 months, or 6,000 miles, and perform a full tune-up once a year or 12,000 miles.

Today, doing any ignition related tasks once every 100,000 miles is more like it, making 12,000 mile service interval seam excessive.

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 Post subject:
PostPosted: Thu Apr 14, 2011 5:00 pm 
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Turbo EFI
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Joined: Tue Feb 22, 2005 5:35 pm
Posts: 1044
Location: Maine
Car Model:
Don't be satisfied until you're getting better than 20 mpg... 23+ if you're babying it at all.


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 Post subject:
PostPosted: Thu Apr 14, 2011 5:16 pm 
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EFI Slant 6
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Joined: Mon Dec 20, 2010 8:52 pm
Posts: 414
Location: Gresham, OR
Car Model:
after i did a tune up on mine i got 18, and thats a truck. Just recently when i filled up i was getting 12.3. I went a week babying it as much as my lead foot would let me and managed to get 14.4 mpg just by babying it some and bringing my shift points down a few hundred rpms. Im hoping i can get back up to 18.

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Old truck: 82 D150 225, 2bbl, dutra duals, 2.5" straight pipe to dual 2.5" tail pipes. Mud tires, 4spd, old forest service truck.
Current truck: 98.5 Ram 2500 ccsb, sport, 24v cummins, 5spd, 4.5" lift, 35's, 5" straight pipe.


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