TJ to LJ Conversion

S

sac_Jeep

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Joined
May 2, 2022
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22
Location
Louisiana
First off, love to see forums are still being used! FB Groups just aren't the same...

Long time Jeeper, my first one was an 2006 Silver Rubicon and have been hooked since. That being said, being from South Louisiana with big dreams of wheelin out West was just that when I started my Jeep life. Fast forward to now where my family has a place in Colorado and we spend a fair amount of time up there. But.... My offroading up there has strictly been in the SxS world. Every year we packed up 5 SxS's and wheel for 6 weeks straight and the whole time I think to myself, "This is awesome!! But....It would be better in a Jeep!


IMG_9350.jpg


So.... After last years trip I sold my X3 and started looking for a Jeep to build! Knowing I wanted an LJ, but also knowing I wasn't going to use any of the factory drivetrain the search came up empty handed because as you know, the price they bring these days are through the roof! Then I came across Motobilt stretching their YJ and Genright doing their new conversion got me thinking I could do the same thing. Well finding a parts TJ with a good tub and clean VIN is way easier and cheaper. So it didn't take long to take delivery of just that, even scored it in my home town.

IMG_0910.jpg


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So now 1 piece of the puzzle had been found and secured it was time to start thinking about the next piece. Reached out to Motobilt and they said they will be doing R&D on the TJ after they finish the YJ build. Then researching Genright's kit got pretty pricey, still going to use their interior kit though. Now the hunt for a factory LJ frame was the mission because I could use off the shelf suspension kits. After a few dead ends, a friend of mine sent me a link to one on FB Marketplace. Was a great price & in good shape. Told the guy I wanted it no questions asked. So the 30hr round trip begins! The guy was of course a Jeep guy, had a nicely built LJ and a few other older trucks. Turns out the frame came from Watson and Sons' Jeep Salvage, a place I had reached out to earlier.

2D71119F-999F-4BB7-8A21-D2F73EAA7A8D.JPG


IMG_1619.jpg


So now I have 2 major pieces of the puzzle in my hands!! Which brings me to my next one. I knew all along I wanted to LS swap it and I have been sitting on an LQ4/4L80 combo for a while now. Being hands on with many LS engines and swaps, I'm confident with them. I've used Holley as my source for LS swap parts in the past, so it was a no brainer to use them again. With supplies being how they are these days, soon as seen Summit had them in stock, I jumped on them.

IMG_1678.jpg


So the pieces are coming together! My new shop is almost ready for a project and the LJ build will be the first one.

IMG_1681.jpg


Overall build plan:

Stretch tub to an LJ using Genright's interior kit
Savvy Midarm Kit and hopefully most of their catalog
LS Swap with LQ4 with their a 4L60 or 4L80 (Haven't made up my mind)
Axles are the biggest item.. I know what I want (Spidertrax Fab9's) but the bank account frowns at those. I can get my hands on some JK Rubicon 44's for a great deal but I'm not sold on JK width axles and how long they will last with 37's and LS power.. I'll be following the girl on YouTube that is running that setup to see how they hold up.
Nest big ticket item is t-case of course. Several options there.. 241, Atlas or the Rock Box Dana300 from Midnight Metalworks.
 
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sac_Jeep said:
First off, love to see forums are still being used! FB Groups just aren't the same...

Long time Jeeper, my first one was an 2006 Silver Rubicon and have been hooked since. That being said, being from South Louisiana with big dreams of wheelin out West was just that when I started my Jeep life. Fast forward to now where my family has a place in Colorado and we spend a fair amount of time up there. But.... My offroading up there has strictly been in the SxS world. Every year we packed up 5 SxS's and wheel for 6 weeks straight and the whole time I think to myself, "This is awesome!! But....It would be better in a Jeep!


View attachment 327570

So.... After last years trip I sold my X3 and started looking for a Jeep to build! Knowing I wanted an LJ, but also knowing I wasn't going to use any of the factory drivetrain the search came up empty handed because as you know, the price they bring these days are through the roof! Then I came across Motobilt stretching their YJ and Genright doing their new conversion got me thinking I could do the same thing. Well finding a parts TJ with a good tub and clean VIN is way easier and cheaper. So it didn't take long to take delivery of just that, even scored it in my home town.

View attachment 327564

View attachment 327565


So now 1 piece of the puzzle had been found and secured it was time to start thinking about the next piece. Reached out to Motobilt and they said they will be doing R&D on the TJ after they finish the YJ build. Then researching Genright's kit got pretty pricey, still going to use their interior kit though. Now the hunt for a factory LJ frame was the mission because I could use off the shelf suspension kits. After a few dead ends, a friend of mine sent me a link to one on FB Marketplace. Was a great price & in good shape. Told the guy I wanted it no questions asked. So the 30hr round trip begins! The guy was of course a Jeep guy, had a nicely built LJ and a few other older trucks. Turns out the frame came from Watson and Sons' Jeep Salvage, a place I had reached out to earlier.

View attachment 327607

View attachment 327608

So now I have 2 major pieces of the puzzle in my hands!! Which brings me to my next one. I knew all along I wanted to LS swap it and I have been sitting on an LQ4/4L80 combo for a while now. Being hands on with many LS engines and swaps, I'm confident with them. I've used Holley as my source for LS swap parts in the past, so it was a no brainer to use them again. With supplies being how they are these days, soon as seen Summit had them in stock, I jumped on them.

View attachment 327609

So the pieces are coming together! My new shop is almost ready for a project and the LJ build will be the first one.

View attachment 327610

Overall build plan:

Stretch tub to an LJ using Genright's interior kit
Savvy Midarm Kit and hopefully most of their catalog
LS Swap with LQ4 with their a 4L60 or 4L80 (Haven't made up my mind)
Axles are the biggest item.. I know what I want (Spidertrax Fab9's) but the bank account frowns at those. I can get my hands on some JK Rubicon 44's for a great deal but I'm not sold on JK width axles and how long they will last with 37's and LS power.. I'll be following the girl on YouTube that is running that setup to see how they hold up.
Nest big ticket item is t-case of course. Several options there.. 241, Atlas or the Rock Box Dana300 from Midnight Metalworks.
Click to expand...
What width axle are you thinking? I've been eye balling a trail-gear rock assault builder housing lately.
 
Sounds like a cool project. Question: Since you are stretching a TJ body to fit on an LJ frame, how will you deal with the different relative locations of the rear wheel wells and axles?
 
NashvilleTJ said:
Sounds like a cool project. Question: Since you are stretching a TJ body to fit on an LJ frame, how will you deal with the different relative locations of the rear wheel wells and axles?
Click to expand...
Genright makes a body stretch kit that will turn the tj body into an LJ body
 
The GR TJ to LJ body should work with the LJ frame, you may just have to modify/move the cross-member/body mounts. Heck, you can make anything work with a cut off wheel and welder. With the GR squared off inner fenders, you won't be able to use a stock back seat, you will have to use a narrower Corbeau or PRP.

Having said that, I would recommend doing your own research and not taking my word for it.
 
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gasiorv said:
The GR TJ to LJ body should work with the LJ frame, you may just have to modify/move the cross-member/body mounts. Heck, you can make anything work with a cut off wheel and welder. With the GR squared off inner fenders, you won't be able to use a stock back seat, you will have to use a narrower Corbeau or PRP.

Having said that, I would recommend doing your own research and not taking my word for it.
Click to expand...
Except now thinking about it, idk if their frame stretch uses the arch or not… wonder if there will be room for that
 
starkey480 said:
Except now thinking about it, idk if their frame stretch uses the arch or not… wonder if there will be room for that
Click to expand...
On a TJ, it pushes the stock spring backwards and down within the arch. It's the equivalent to a thick spacer to get a 4" lift.
 
starkey480 said:
Except now thinking about it, idk if their frame stretch uses the arch or not… wonder if there will be room for that
Click to expand...
Should be, the GR body is only the flat floor and the squared inner fenders. The squared inner fenders are on the inside plane of the original inner fenders.
 
B00mb00m said:
What width axle are you thinking? I've been eye balling a trail-gear rock assault builder housing lately.
Click to expand...
Really want to run some Fab9’s. Still researching which ones and best route. Spidertrax catches my eye of course, but the Trail Gear‘s price point is also hard to ignore.
NashvilleTJ said:
Sounds like a cool project. Question: Since you are stretching a TJ body to fit on an LJ frame, how will you deal with the different relative locations of the rear wheel wells and axles?
Click to expand...
TSand05 said:
From my understanding it is meant to be used with their TJ to LJ frame stretch, not an LJ frame
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Apparition said:
That was mine as well but I haven’t dug into it.
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gasiorv said:
Should be, the GR body is only the flat floor and the squared inner fenders. The squared inner fenders are on the inside plane of the original inner fenders.
Click to expand...
From my research in watching the tech videos & reading comments on IG, their frame stretch is based off of all factory body mounting points. So “in theory“ cutting my body where they say cut it and use their interior kit to fill in the gaps should work. As for the wheel well opening, they just use full corner armor to dictate where the wheel centerline will be. Only piece that has to be welded is the section of channel where the soft top windows slip into.

freedom_in_4low said:
Probably my neighbors.

https://www.youtube.com/c/JeepGearGadgets
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freedom_in_4low said:
yes but his comment referring to her was specifically targeted to their use of 37s on JK axles with an LS swap. Or at least that's how I took it.
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Thats who I was referring to. I get her channel & her husbands mixed up. She wheeled it pretty hard on the shakedown run.. More whiskey throttle than I was expecting. I certainly don‘t want to skimp on axles. But if they seem to be holding up on hers, hard to overlook a set of JKR axles. In my mind I’m thinking it will be a Fab9 in the rear and JK 44 in the front until it forces my hand.
 
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