5.3L Vortec Swap

[EVILBOB]

What kind of mpg and performance can one expect after doing an LS swap on a FSJ? I have a 2007 5.3l and 4l60 that I am getting ready to install it into my Scrambler, but I might be getting my hands on a Wagoneer. Not sure which vehicle would benefit more, so any advise would help, thanks.

[fsj1979]

I am getting 16-17 mpg on mine. Mine is from an 03, but should be similar. Mine is a combo of city/highway and I'm at 5,000 feet where I live. I have heard of some guys getting as much as 21 mpg. By-the-way, welcome aboard. This place is full of GREAT info. The link to my swap is below, if you want to check it out.

[okjeep]

I'm running about 10-11 in our YJ. 37's with 4:56 gears. I am looking at stepping down to 4:10's since we are running a 4.3 atlas. it's a 2009 5.3 HO with a 700r-4. I think the computer and 4l60e offers much better economy.

[EVILBOB]

Thanks for the replies. I used to own a 76 Cherokee with a 401 and only got 11 mpg, so being able to get into the mid-to-high teens does not seem too bad. My Scrambler gets 16-18 with the 4.2 and will do great with 5.3, but I'm guessing the FSJ would benefit more for the mpg increase, due to the size and weight of the vehicle. Next thing for me to consider is the ease of the engine swap and cost...

[Randyzzz]

I have a 5.3/4l60e/4.56/35" setup in my Scrambler. 20 mpg on the highway so far, I'm sure it will do better... It's a hoot to drive though...like a rocket ship with an on/off switch.

[EVILBOB]

Originally Posted by Randyzzz

I have a 5.3/4l60e/4.56/35" setup in my Scrambler. 20 mpg on the highway so far, I'm sure it will do better... It's a hoot to drive though...like a rocket ship with an on/off switch.

Hey Randyzzz, I thought that was you from CJ-8 forum. I was looking at your build thread again and all I can say is AWESOME! I think I'll have to do the 5.3 in the CJ8, then shoot for the FSJ afterwards. I need to get get started asap or it will never get done.