Hello I have an 08 JKU and I’d like to see what a v8 swap would run me. I know axles and driveshafts will be needed just trying to figure out a price and all the miscellaneous items I’d need to get to do it. Thinking 4L80 transmission.

 

Look at RPM Extreme and Motec sites to see what their swap kits cost. It is a lot more expensive than I thought it would be.

 

Welcome to JKF. Lots of good info here so hope you stay around and tell us of your adventures in both mods and wheeling.

I installed an LT 5.3/8 spd auto in my 2008 using the kit from Motech in Las Vegas. Sure you can do it yourself but mine still sees the Jeep and Chev ECUs chat to each other on Canbus and all the gauges and features work. So basically I can get into this thing and drive from one end of the country to the other without fear of any upsets. 4 speed transmission will be a shortfall as it won't utilise the power you are putting in, run out of gears wheeling, you would have to get an Atlas type TC to get your lower gearing for wheeling or have really low diff gearing like 4.88 or 5.13. Then you lose highway speed. I recommend the 6L80/LS 5.3 combo/4.10 gears. If your Jeep is not abused in the way you drive you can leave the axles in there but the transmission moves rearward with adaptors. So need new u-joint shafts shorter rear and longer front. Not sure what you want to end up with but high end using Motech or other kits with all the bits and pieces including even radiator/fan will run you about $9k, good engine tranny combo $3k, shafts about $1500, suspension kit $1500-2500, Then about $2-3K for all the little things (there are lots). This gets you a daily driver that is reliable and BTW I got an increase in gas mileage of 15-20% over the V6 and 355HP on tap. Will even accellerate in 8th gear good enough to pass at about 70mph.
Other end of the scale is hard to predict if you are bits and piecing it but I bet you will use up about $6K doing it that way. Very difficult to get it all wrking though but there was one commercial outfit here that did a cheap conversion but I question what they actually spent as they had parts available that they did not have to buy. A conversion like this will actually devalue what you have unless it is a professional style conversion. Guy up here in Calgary has a 2008 Ruby JKU with professional kit installed 5.7Hemi/(unsure of speeds) auto with all systems and gauges functiona, suspension, wheels, shafts etcl and he cannot get $28K CDN for it which is $20k USD.
Hope you get something from my reply but it is what I basically imply to others as well as a V8 conversion is a mammoth task to undertake. Not like back in 1977 my friend bought a new V8 CJ5 drove 30 miles on it to a shop and dropped a 390 Javelin motor in it same day and drove next day. That thing would just about throw you out over the back seat on to the road. Easier to get you nippers on an Arizona CJ7 and put the V8 in.

 

sound like a lot you plan to do if you do go with a 4l80E there is a guy who makes control mods for them check them out name is e trans control.

 

Whether it’s a LS or Hemi swap, you’re going to spend about 15-20k with a conversion kit and a 8-speed doing it yourself. I would agree with Sixty4x4 that you’re not taking full advantage of a V8 if you use your 4sp. Can it be done? Yes but it drives so much better with an 8 speed. Even in the Hemi world, it is recommended to go with the 8speed instead of the factory jk 5sp auto.

 

Did not realized it’s an old thread.

 

Not that old so feel free to input still. Not sure where the OP went but there was a dude that did an LS swap into a Jeep and it was pretty cheap with bastardized Jeep dash etc. One used to be able to buy the interface computer off Robbie at Motech but not sure if he still does that. That makes the Chev to Jeep functions work with stock Jeep stuff one keeps.

 

Yup. I thought about doing the LS swap also but heard so many issues with comm between the Chevy ecu and Jeep. I’m sure technical advancement are so much better now for the LS. I chose to go with the Hemi because it’s literally plug and play.