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318 mpg #2522328
07/15/18 10:50 PM
07/15/18 10:50 PM
Joined: Jan 2003
Posts: 3,920
n.e. pa.
6
65rbdodge Offline OP
master
65rbdodge  Offline OP
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6

Joined: Jan 2003
Posts: 3,920
n.e. pa.
I finally checked the mpg in my desoto while driving to Carlsile. I was shocked that it was 26mpg! It’s a .030 over LA roller 318 with magnum heads, 3x2 9super7 carbs, a reground roller cam(not big only .436 lift) block hugger headers and 2.25” dials with x pipe. It’s an 833od with 323 gears.

Re: 318 mpg [Re: 65rbdodge] #2522329
07/15/18 10:51 PM
07/15/18 10:51 PM
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda Offline
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Supercuda  Offline
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Posts: 14,889
up yours
My 87 Diplomat would get that but it depended on the speed I was running, 65 or less yep, 70+ not so much.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: 318 mpg [Re: 65rbdodge] #2523139
07/17/18 04:17 PM
07/17/18 04:17 PM
Joined: Oct 2004
Posts: 16,452
Canada
CrAzYMoPaRGuY Offline
I Live Here
CrAzYMoPaRGuY  Offline
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Joined: Oct 2004
Posts: 16,452
Canada
I have two 318 cars, the wideblock gets awesome mileage and the Cordoba was a gas pig UNTIL I replaced the exhaust. Was a single exhaust with manifolds and a cat- I put headers and 2 1/2 mandrel bent duals out the back, a little more power but WOW way better gas mileage!!!!


CrAzYMoPaRGuY
Re: 318 mpg [Re: CrAzYMoPaRGuY] #2524604
07/20/18 03:52 PM
07/20/18 03:52 PM
Joined: Jan 2003
Posts: 16,376
D
dogdays Offline
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Joined: Jan 2003
Posts: 16,376
My 318 Poly got a maximum of 16mpg with 3.23 gears and 32" tall rear tires. That's with the carb leaned out, which means down jetted until it has lean surge then one jet number higher.

I replaced it with an '86 318 roller motor. I home ported the 302 heads, swapped in a 360 /5.9Mag camshaft, added the cast iron EGR 360 manifold, adapted the Poly's carb to it. So same carb not changed and same exhaust system with stock low perf manifolds piped back to the exact same exhaust system. This is a 100+ K engine. First tank was 22mpg! That's in a '64 D100 long sweptline.

That chamber is magic.

R.

Re: 318 mpg [Re: dogdays] #2524662
07/20/18 06:17 PM
07/20/18 06:17 PM
Joined: Sep 2016
Posts: 236
British Columbia, Canada
Old Ray Offline
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Old Ray  Offline
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Joined: Sep 2016
Posts: 236
British Columbia, Canada
Originally Posted By dogdays
That chamber is magic.


Hi, Sorry I'm old, not that smart, and not up on things, what chamber ? confused

Re: 318 mpg [Re: 65rbdodge] #2524681
07/20/18 07:07 PM
07/20/18 07:07 PM
Joined: Jan 2003
Posts: 3,575
The Netherlands
BigBlockMopar Offline
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BigBlockMopar  Offline
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Joined: Jan 2003
Posts: 3,575
The Netherlands
Cylinder headchamber.
'302' heads are known as swirl type heads and promote better combustion and burn.

I wish I could say I had the same experience with the '302' heads but both on my previous stock 318 rollercam engine with 302s and the current 11.3:1cr 360 with polished 302s in my daily driver produce the same 'lousy' mileage of around 11-12mpg.
But I still suspect the A518 and its '60s torque convertor behind both engines being the main culprit here.

Re: 318 mpg [Re: 65rbdodge] #2524693
07/20/18 07:36 PM
07/20/18 07:36 PM
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda Offline
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Supercuda  Offline
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Joined: Sep 2007
Posts: 14,889
up yours
The 302 headed roller cam 318's came with lockup A998's and 2.45 rear gears. Not an OD trans or high stall converters, or steep gears.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.






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