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Unread 01-09-2010, 03:55 PM   #1
Viencent
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AMC 304 mpg

what is good mpg for a 304 with 33 tires, just filled up the new jeep and got about 12 mpg, combo highway/city. also any good tips for this Engine like the nutter?

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Unread 01-09-2010, 08:25 PM   #2
Viencent
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bump...any pointers at all for this 304?
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Unread 01-09-2010, 09:19 PM   #3
4Huskrs
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I have a 304 and I do not get very good mileage.
Ron
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Unread 01-09-2010, 09:44 PM   #4
Pathkiller
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No such thing as a Nutter for AMC V8's as they never used the computer controlled carb. Best you can do is a good tune up and drive it sensibly.
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Unread 01-09-2010, 10:37 PM   #5
semikrazy
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I had a 304 in my '75 and it never got less than 20mpg. It was mostly stock only had a mild cam and headers with a 2100 carb running 32" Firestone ATX. Of course it was when gasoline was gasoline. My '76 with the 258 gets way worse fuel mileage, around 15mpg.
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Unread 01-10-2010, 04:28 AM   #6
Viencent
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Thanks for the input, so anyone got some tips for this 304? things to watch for or upgrade?
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Unread 01-10-2010, 05:47 AM   #7
Area.3.Fiftyone
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Quote:
Originally Posted by Viencent View Post
thing to do with a 304 for an upgrade?
Buy or borrow one of these:



And then do this:



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Last edited by Area.3.Fiftyone; 01-10-2010 at 06:44 AM..
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Unread 01-10-2010, 05:54 AM   #8
John Strenk
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Cute but I think here is a better ignition system I believe or the 304.

Search for JeepHammer post on the subject.

Funny thing is, there is a member on here with an 8 sec 1/4 mile CJ and he get 14 mpg with that V8.
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Unread 01-10-2010, 06:36 AM   #9
Viencent
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thanks fond JeepHammers post and it has some great info, wil be doing that upgrade soon
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Unread 01-10-2010, 06:44 AM   #10
jfwireless
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My stock 1976 CJ-7 with a 304 only got around 10-12 MPG before the TBI conversion, that really helped, now around 18 mpg. But I am running a TH400(very heavy internally) and a full time QT transfer case. If it was not for the drive train most likely would get over 20 mpg. My 304 is getting tired, compression down to around 110-130 lbs on all 8 cylinders, but still running very strong with the junkyard TBI conversion. I have a 360 I have been working on for a long time, hopefully when I get that complete we will see how the junkyard TBI conversion works on a mechanically sound engine. I am looking forward to that day. It will be optimized with a special ground camshaft for TBI operation. That should help significantly.

My axle ratios are stock 3.54, and running 31 inch Dueler HT tires.

Jim
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Unread 01-10-2010, 07:11 AM   #11
halpeters
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I have a stock 78 cj-7, 304, 3 speed, 3.54 axles, with 31" M/T's and get around 12-15 MPG, with current pump gas "up to 10% ethenal" stuff...

My odometer reads about 8% low due to larger tire size over stock. Be sure to take tire size into consideration when calculating gas mileage.
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Unread 01-10-2010, 07:18 AM   #12
Viencent
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didnt think about tire size. so whats the ratio for 33's?
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Unread 01-10-2010, 07:23 AM   #13
BioTex
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My stock 304 (except an RV Cam) with MC 2150, 33's and 4" lift gets 14-15mpg.
I have 3.31 gears.
I have the Team Rush upgrade.
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Unread 01-10-2010, 05:14 PM   #14
halpeters
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Quote:
Originally Posted by Viencent View Post
didnt think about tire size. so whats the ratio for 33's?
Well, that depends - larger tires can have a lot of variation between brands, style, and wear.

The best way is to use a GPS. Most have a setable trip meter. On your next road trip, write down your odometer reading, and zero the trip meter. At the end of your trip divide GPS miles by odometer miles. This will give you the adjustment factor. Be sure the GPS doesn't loose lock - no woods trip for this...

Or, you can use MPH - drive at 60 MPH on the speedo, and see what the GPS says - same formula - GPS MPH divided by speedo MPH = adjustment factor.

For to figure out true miles driven, take your odometer miles and multiply by the adjustment factor.

For my Jeep with 31's the adjustment factor is 1.08.

Hope that helps,

Hal
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Unread 01-10-2010, 06:41 PM   #15
h2ojeep
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When I first got my CJ7 304, 354 gears, 31in tires; I was getting 7-8 MPG, did a complete tune up, teamrush upgrade and now I average about 13MPG.
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