I know several people in this thread know much more than I do, but I disagree with all of this. I think the 4.8L I have sucks with a 5spd, and no way in hell would I want it in a jeep with an auto. The only reason is the torque curve. This engine has half the power below 4,000 RPMs, its probably less than your jeep. Those gears will help, and the tires will hurt. A 5.3L crankshaft will drop that torque curve so it starts around 2200. It would let you just drive it most of the time off road. Otherwise, you are going to be doing A LOT of auto shifting

 

You have to do crank and rods- can't just swap cranks

But, you would get flat top pistons out of the deal and have an iron "L33" by the end of it

The 4.8 is not a terrible motor, and it's not quite half the power below 4k. According to this thread: https://www.s10forum.com/threads/lsx...0l-lq9.330477/ ------ Its about 25hp and 25tq down on a 5.3 at 4k. What the 4.8 does shine in is its ability to spin. If I could find a good deal on a 4.8, I would totally reconsider LS swapping my Ranger. I think 4.8s are great for small/light vehicles that don't need "oomph"

 

For the OPs goals and setup, I would've recommended a cam with intake in the 206-209 range (BTR, TSP, Summit). if it's too late to get a different cam, and a displacement bump is not in the cards, then I would at least increase the CR to 11:1 instead of the planned 10.5:1.

 

Totally different scenario, but my 12 crewcab 2wd 4.8 is lacking below 4K. 3:90 rear gear, LT's and tune, it couldn't leave a mark if it tried. In a Jeep auto?....lacking IMO

 

I did think about swapping my old 5.3 into a Jeep but decided not to. It woulda been stock

 

Probably a 1000 or more lbs difference between your '12 and his Jeep

 

May as well be 5K lol....waiting on a 5.3

 

Realistically, all the LS motors are so fantastic, you can't go wrong with any of them. Even the "weak" LS1 can still make 650whp reliably, if you're smart about how you abuse it

Doesn't mean the 5.3 isn't better than the 4.8, application dependent

 

Sorry guys. I am way behind. Got real sick for 3 weeks. Just now about to start back on this swap.

my 4.8/5.3 block had two cylinders trashed. Then I bought another block and it was cracked.. so I bought a disassembled 2000 ls1 5.7 short block with stock style pistons and stock rods. I got the cam bearings installed , the btr cam and the crank. Then I felt sick the next day.. I still need to check the ring gap, then finish assembly. I'm using the 862 heads with 2" intake valves and the chambers are now 61cc after milling. It will have a higher compression then I thought.

Hopefully this btr cam isn't too small now? Will it still work with a stock converter th350?

The plus side is the weight savings of the aluminum block 5.7 ls1 vs iron ls block is 100# . That makes the ls swap only 80# heavier then current 4cyl.
The jeeps axles are from 2004 Ford superduty. Dana 60 and sterling 10.5.

 

If anything the cam is a better match than before and more likely to work with a stock stall.