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Old 09-20-2019, 12:09 AM
mwood65's Avatar
mwood65 mwood65 is offline
258 I6
Join Date: Jul 17, 2017
Location: Payson Arizona
Posts: 428
General quesion for anyone with an LS install

I could never afford it but am just curious.....

Anyone who has installed a LS1, LS3 in a full size jeep or bought one that way.

I am curious what kind of fuel mileage they will get with an auto or manual.

My C5 Corvette with a LS1 and a 6 speed would get right at 30 mpg on the hwy.

Now I realize a FSJ is way heavier, geared different and nowhere near as aerodynamic.....

Just curious what they get in a FSJ.
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Old 09-20-2019, 06:26 AM
KillyMcGee KillyMcGee is offline
232 I6
Join Date: Aug 26, 2019
Location: Arkansas
Posts: 41
Don't have one, am curious as well. But considering these things are close to the same weight and block shape of a K5 blazer, I'd expect a normal stock swap would net a person 15-18mpg on the highway depending on gears and tire size. Less aerodynamic than a Tahoe, but weight slightly less.
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Old 09-22-2019, 06:12 PM
joe joe is offline
Join Date: Apr 28, 2000
Location: PNWet, USA
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Originally Posted by mwood65
Now I realize a FSJ is way heavier, geared different and nowhere near as aerodynamic.....

You pretty much nailed it.
If you need to get 30mpgs in a FSJ...son ya bought the wrong car. Even with a crazy expensive computer controlled dsl motor, elec computer controlled OD trans and proper axle gearing transplant you prolly won't see 30 mpg. These are hobby cars not fuel saver friendly commuters. Ya need 30 mpgs, keep driving your computerized Corvette.
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Old 09-23-2019, 06:11 AM
conehead conehead is offline
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Join Date: Apr 24, 2006
Location: pennslyvania
Posts: 212
Don't put a Chevy engine in it, their a dime a dozen. You're never going to get 30 mpg. The AMC 360 is a great engine so I left it in my Wagoneer. It has Howell throttle body fuel injection, got rid of the choking pollution crap, a couple other improvements and a NV4500 five speed and I can get 20 MPG on the highway if I take it easy.

Last edited by conehead : 09-23-2019 at 06:17 AM.
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Old 09-23-2019, 06:42 AM
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8man 8man is offline
304 AMC
Join Date: Jan 04, 2011
Location: Bryan, Texas
Posts: 1,558
I did the LS swap. It has way more power than the original 360. As far as gas mileage goes, who knows, I've never checked it. I do know that it is not as fuel efficient as my wife's Durango, but then I didn't do it for the fuel mileage.
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