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 Post subject: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Sat Oct 25, 2008 6:19 pm 
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Killed his Hooptie Geo Prism
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Location: Fort Wayne, IN
I know, I know...Fuel Economy and Jeep should never ever be used in the same sentence.
Also, I know that a AMC 360 is a very thirsty V8

So...I digress...

I was looking at a late 80ish YJ with no engine or transmission.
It appears to be complete, rust is not bad.
This YJ was a 2.5L four cylinder with a 5 speed.

From my FSJ wanderings, I have a couple of AMC 360s, a TF727 and a NP208 transfercase.

I think I know of where I can get some CJ V8 parts, like engine mounts, headers (probably rusty as the CJ carcass is a pile of Midwest rust)
(I am assuming that CJ V8 mounts would go in a TY without much difficultly)
Things I know I would need, would be a wiring harness, V8 radiator, driveshafts and a shifter.

Thought about marrying some of the parts together to make a driver.
BUT, if this 360 powered YJ is gonna get 10 miles per gallon, then I may pass.

So, how would a stock 4.0L I6 compare to a stock AMC 360 in fuel economy?
Researching, I have discovered that a 4.0 with 5 speed is suppose to get near 20 mpg on the highway.

I know that a AMC 360 with a slushbox will not get that, but I am wondering how close it would come?
Secondly, wonder how much better mileage a 360 and a NV3550 would get over a 360/727?
Since this YJ is a manual, it maybe easier to install a NV3550 instead of rigging up a shifter the 727.

My thoughts are that a 360 in a lightweight Jeep (as compared to its native Wagoneer of near #5000)
would not need to work as hard and be easier on fuel.

Okay, maybe I could get okay mileage in a 360 powered YJ, but with all that fun under the hood, how would I ever keep my foot out of it?
OOO YESSS!!

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Bryan Smith
2004 KIA Optima (wife 's DD)
1999 Jeep Grand Cherokee Limited (my DD)
1993 GMC 3500 extended length cargo van, 6.2L Diesel powered.
1982 J10 - current project, replacement AMC 360 sitting in the engine bay.
1981 J20 - stock with a super kewl commercial flat bed (stored, long term Diesel dually project)


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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Mon Oct 27, 2008 10:19 pm 
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Baby puncher
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a block of wood under the gas pedal...lol
I dont know of anyone with a 4.0 powered tj that gets anywhere close to 20mpg

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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Tue Oct 28, 2008 11:59 am 
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mr. snuffleupagus
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mudpuppy wrote:
a block of wood under the gas pedal...lol
I dont know of anyone with a 4.0 powered tj that gets anywhere close to 20mpg


really...we are lucky to get 14 mpg with a 4.0 tj...where did you here a 4.0 tj can get close to 20 on the high way? the only way i can think is they geard the hell out of it with tiny tires

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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Tue Oct 28, 2008 2:29 pm 
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Thread Necromancer
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My old TJ had 33" and 3.73s and would hit 18-20mpg on the highway... around town and what not htough, I usually saw around 14-15.
I say do it. You may have a bit more problems with the motor mounts than expected though, the frames a bit different.

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Jeeper4Life wrote:
noone means any harm and that it's all in fun.. but then there's kennedy..

'46CJ2a/buggy project in the works, yeah, still have those parts.
'14 Chebby Silverado, 4x4
'88 GMC S15 Trail Gypsy
A sweet lawn mower
Motorcycles: '14 HD FLHTCU, '92 HD FXRS, '26 HD JD, '02 Suzuki DRZ400, '56 Cushman Eagle, '48 Simplex ServiCycle, '72 Honda MiniTrail50, '81 Yamaha YR250, Probably some other stuff
"Tell me and I'll forget. Show me and I'll remember. Involve me and I'll understand." - Confucius
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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Tue Oct 28, 2008 9:46 pm 
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mr. snuffleupagus
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kennedy wrote:
My old TJ had 33" and 3.73s and would hit 18-20mpg on the highway... around town and what not htough, I usually saw around 14-15.
I say do it. You may have a bit more problems with the motor mounts than expected though, the frames a bit different.



yeah maybe with the wind at your back at 30 knots

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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Wed Oct 29, 2008 7:44 am 
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Thread Necromancer
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Location: Omokok, NI
Blue wrote:
kennedy wrote:
My old TJ had 33" and 3.73s and would hit 18-20mpg on the highway... around town and what not htough, I usually saw around 14-15.
I say do it. You may have a bit more problems with the motor mounts than expected though, the frames a bit different.



yeah maybe with the wind at your back at 30 knots


naw, I usually just drive like your grandma

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Jeeper4Life wrote:
noone means any harm and that it's all in fun.. but then there's kennedy..

'46CJ2a/buggy project in the works, yeah, still have those parts.
'14 Chebby Silverado, 4x4
'88 GMC S15 Trail Gypsy
A sweet lawn mower
Motorcycles: '14 HD FLHTCU, '92 HD FXRS, '26 HD JD, '02 Suzuki DRZ400, '56 Cushman Eagle, '48 Simplex ServiCycle, '72 Honda MiniTrail50, '81 Yamaha YR250, Probably some other stuff
"Tell me and I'll forget. Show me and I'll remember. Involve me and I'll understand." - Confucius
Image.................................................... ImageImage
"Concern yourself with what is right and you'll never second-guess that decision"
I'm not really an asshole, I just play one on the internet!


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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Wed Oct 29, 2008 8:17 am 
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Lights fires at 3am & makes syrup
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There was one time I got above 16mpg out of my YJ....

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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Wed Nov 05, 2008 9:43 am 
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Jeeper in IN
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Location: Noblesville, IN
Well, I have the AMC 304 V8 in mine w/ T-15 3 speed tranny. The 360 is basically the same as the 304, just bored out a bit. All I can say is that I get about 7-7.5 mpg out of mine. If I saw 14 mpg, I wouldn't know what to do with myself.

So to answer your question, I doubt you're going to see anything anywhere near what you're hoping. AMC and fuel economy is an oxymoron.....

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DD: 2006 Nissan Titan Granite Crew Cab SE 4x4 w/ Big Tow, 35x12.5x17 Cooper Discoverer STT and many more modifications.

Jeep: 1974 CJ5 w/ AMC 304. 2.5" Pro Comp springs w/ Old Man Emu shock and 32x11.5x15 BFG M/Ts. Dana 44 rear and Dana 30 front.
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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Thu Jun 11, 2009 11:43 pm 
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Jeeper in IN

Joined: Fri Jun 05, 2009 9:15 pm
Posts: 29
Location: Spencerville, OH
Juday wrote:
Well, I have the AMC 304 V8 in mine w/ T-15 3 speed tranny. The 360 is basically the same as the 304, just bored out a bit. All I can say is that I get about 7-7.5 mpg out of mine. If I saw 14 mpg, I wouldn't know what to do with myself.

So to answer your question, I doubt you're going to see anything anywhere near what you're hoping. AMC and fuel economy is an oxymoron.....


X2, I have a 304 V8 with an AMC TH400 auto behind it and I am lucky to get 10 MPG on the highway, on the other hand I had an 89' XJ with a 4.0L, 6.5" lift, 33's and it didn't do too bad, ok, maybe it did do bad, but was way better then my CJ with a mild cam. Just say , screw it and go SBC 350/TH400/ 203/205 doubler, your starting with a clean slate not having a motor or trans in it, V8 = FUN!!! Just my 2 cents :tu2:

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 Post subject: Re: Fuel Economy in a AMC 360 powered YJ
 Post Posted: Sat Jun 13, 2009 6:41 pm 
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Killed his Hooptie Geo Prism
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Joined: Mon May 08, 2006 8:49 pm
Posts: 202
Location: Fort Wayne, IN
This was last fall...I saw a near give away engine-less YJ and I had some FSJ parts...thought I could marry the two for cheap.
I let the YJ pass.
So, this is all a mute point.

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Bryan Smith
2004 KIA Optima (wife 's DD)
1999 Jeep Grand Cherokee Limited (my DD)
1993 GMC 3500 extended length cargo van, 6.2L Diesel powered.
1982 J10 - current project, replacement AMC 360 sitting in the engine bay.
1981 J20 - stock with a super kewl commercial flat bed (stored, long term Diesel dually project)


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