Higher horses, higher revs & even higher torque, a streetable LJ engine swap

[toximus]

I was surprised by how much farther back the I6 was able to sit in the engine bay when compared with the V8 - due to the shape of the firewall. When I started mine I had assumed I’d have much more room up front given the shorter length of the Hemi - but nit so much.

I had thought that I would be placing the engine as far forward as possible, but it's actually sitting better further back and further down. I moved the engine back further and it's touching the firewall now. I'm thinking about giving the firewall a few taps to make room but I also don't want to shatter the heater box behind it.

The AC condenser was removed from the firewall to make room:

The CTS-V exhaust header is barely touching the old frame side engine mount (which I can remove). But I'm not sure the engine needs to go down any further anyway. If I move the engine down further the header also threatens dumping onto the UCA and not leaving enough room for an exhaust pipe. Once I get the Atlas tucked up I'll be able to correctly set the engine position.

The clearance against the RJ60VXR axle is looking good and has more room that it can come down if needed.

At least with the engine further back and down I won't have to cut a hole in the hood for the alternator to stick out of anymore! The coilover hoop brace fits in which was the highest point.

I need to whack the tub floor to make more room for the Atlas. It's a big boy! Right now it sticks 1-1/4" below the bottom of the frame.

I still need to figure out where the AC compressor can fit on the accessory drive. The Holley low profile mount looks like it will sit about 1" into the frame rail. Which is no good...

 

[NashvilleTJ]

Tox, you should be able to clock the Atlas flat there if you wanted to, but it does take a chunk of body work. What surprised me is that I also had to modify the drivers side inboard seat mount - that was the tricky part for me.

 

[toximus]

Tox, you should be able to clock the Atlas flat there if you wanted to, but it does take a chunk of body work. What surprised me is that I also had to modify the drivers side inboard seat mount - that was the tricky part for me.

You're right about there being some body work! I started with the hammer last night and need to work on it more today. This is the area that the Atlas is sitting for me:

 

[toximus]

I cycled the axle several times and it's tentatively appearing that the cast aluminum pan that came with the LS crate engine is going to clear everything just fine. As long as I place a skid under it, what do you guys think about running it?

 

[NashvilleTJ]

I cycled the axle several times and it's tentatively appearing that the cast aluminum pan that came with the LS crate engine is going to clear everything just fine. As long as I place a skid under it, what do you guys think about running it?

I don’t see any issue with running it, as long as you powder coat it black.

 

[toximus]

My arms ache and my hands have blisters. Now I know why they call it body work... But I think I will be able to get a flat belly skid in!

To get the room I needed for the Atlas, I had to cut a half moon out of the driver's seat support around the trans tunnel. I learned this trick from @mrblaine . After that, I beat and beat on the sheet metal until it raised up to meet where I cut it.

I removed the seat to make the cut, but put it back before hammering so that it wouldn't warp.

I inked my line before cutting:

Cut the slice out:

Difficult to see in the picture, but the lower sheet metal now meets the higher cut. I'll paint this later.

Tucked!

The area lost inside the Jeep is minimal since it's mostly under the seat and console area. My right foot generally sits on the gas peddle so the area lost isn't anything I'm going to miss.

 

[toximus]

I found it on sale, so I ended up buying a Holley 20-160 low profile AC compressor to see how it fits. It barely fits and requires lifting the engine to fit the compressor in.

There's a 1/16" gap between the compressor and the frame:

To account for the engine moving under load, I'm going to notch the frame in that section and weld back in a plate to make room for the compressor.

I really like how the compressor sits down there instead of up high.

To further clean up my accessory drive, I'm considering moving the alternator over to the right side closer to the battery and PDC. This way I won't have to run a cable over top of the engine.

The GoatBuilt 4405 and 4406 brackets seem to fit the bill:

Now I need to decide if I want truck spacing (tucks the alternator in tighter) or f-body spacing (gives me an extra 3/4" in front of the engine for more coolers or a bigger fan).

 

[toximus]

To get better clearance around the front driveshaft, I'm ordering one of these 6L80e angled bulkheads from Australia:

https://www.marks4wd.com/mfk20256

Shipping is expensive at $69. If anyone else wants one let me know and we can combine shipping. I'll be placing my order at the end of the week.

 

[Fouledplugs]

To get better clearance around the front driveshaft, I'm ordering one of these 6L80e angled bulkheads from Australia:

https://www.marks4wd.com/mfk20256
View attachment 207310

Shipping is expensive at $69. If anyone else wants one let me know and we can combine shipping. I'll be placing my order at the end of the week.

Do you know if the AN fittings are steel or aluminum?

Is the bulkhead required? Seen it done on the GM 4 speeds using just the 45 and 90 degree AN fittings.

I’m sure Earls Plumbing offers a solution that fits tighter (that bulkhead looks unnecessarily big) if that matters to you, but would likely cost more.

 

[toximus]

Do you know if the AN fittings are steel or aluminum?

Is the bulkhead required? Seen it done on the GM 4 speeds using just the 45 and 90 degree AN fittings.

I’m sure Earls Plumbing offers a solution but would likely cost much more.

The fittings are steel ORB to -6AN into the aluminum bulkhead from Marks4wd. Meaning, they're replaceable.

I've found lower profile bulkhead fittings than what I currently have (such as this https://www.jegs.com/i/Earls/361/1128ERL/10002/-1) but they all still point outward. They'd probably clear the DS after putting a 120* fitting off of them, but while I'm doing it I figure I might as well get it as far away as possible.

 

[Fouledplugs]

Having made the decision to blindly purchase some AN fittings for my Spidertrax axle breather setup and after talking with Spidertrax and Maximum transmission, I discovered and learned that Earls quality is much better than most import stuff. I have some very high resolution comparison photos in my Spidertrax axle build thread on here.
https://www.summitracing.com/parts/...SpmS9Hab2NXsTRCk0bxjeWMMtOLj7rsIaAnugEALw_wcB

 

[Fouledplugs]

The fittings are steel ORB to -6AN into the aluminum bulkhead from Marks4wd. Meaning, they're replaceable.

I've found lower profile bulkhead fittings than what I currently have (such as this https://www.jegs.com/i/Earls/361/1128ERL/10002/-1) but they all still point outward. They'd probably clear the DS after putting a 120* fitting off of them, but while I'm doing it I figure I might as well get it as far away as possible.

Beat me to it.

 

[toximus]

I have just over 10-1/2" of space between the back of the grill (AC condenser) and the front of the accessory belt with Corvette spacing. The new radiator is 3.75" and the electric fan is 3.75" leaving me with 3.5" with Corvette spacing. I could replace my alternator for a smaller one and keep that Corvette spacing, but since I have the room I decided to go to truck spacing (1.5" further forward) which allows for the most compact placement of the accessory drive. The 2010 Camaro uses the truck spacing so I ordered up a new water pump (ACDelco 251-734) and alternator brackets that work with it. I'll be left with 2" which still leaves options available if I choose to add another cooler.

To share some of my research I won't be using: I think the bracket spacings would be different so I didn't go for it, but I did find the ACDelco 251-816/12681186 water pump which offers the most clearance since it doesn't have a snout. If I was keeping the alternator on the left (driver's) side I would use this pump.

A consequence of moving the engine back and tucking the transfer case up so high is that there's little to no room for exhaust. Before I finalize the mounts I need to mock up exhaust and really would prefer to get a pipe bent up so I know exactly what I'm dealing with. I talked briefly to Stainless Headers Mfg who's about 5 hours from me about their unique exhaust pieces and if they can do the install — they can in 3-4 months, but their pricing is extremely high and I'd only pay it if there's no other way.

I ordered a flexible 2-1/2" pipe to rapidly play around with routing and see where it can fit.

 

[toximus]

The Art-Carr/Winters 4L80 shifter arrived. I played around with fitting it into the console area and adapted it for tap shift with the kit from Radesigns. For now I have the rock gate installed, but I'll probably modify it so it functions the way I want.

 

[toximus]

I wanted to show you guys the difference between the (Camaro?) headers that come with the LS3 and the CTS-V.

CTS-V on top:

The LS3 header hits the UCA on the driver's side and doesn't fit. Here's the passenger side:

CTS-V header is close to the steering bushing. I'll probably have to relocate the bushing.

CTS-V header on the passenger side:

Here's my 1.25" mocked up driveshaft with the front axle at full bump:

I used a vacuum hose to test clearance for the exhaust.

Coming off the header:

I drooped the axle for the picture, but it clears (barely):

My original plan was to go over top of the transmission into a y-pipe. There's about 1/4" of clearance to the body if I have the exhaust pipe routed over top of the 6L80 to Atlas adapter. It's super tight.

This lead me to play with other easier routes. I found that I might be able to loop the exhaust over top of the driveshaft right after the Savvy mid-arm bracket (under the brake pedal). From there I could do a true dual pipe out the back. The downside here is that all of that heat will run right along my fuel and brake lines...

 

[toximus]

Mulling over how to design engine mounts... I'm tempted to cut off the last 2" of the stock mounts and use them as a foundation to build off. I want to get the transmission support in first so I can level the engine since it's leaning a little bit.

 

[5632]

That is claver using a heater hose to test routing an exhaust. On mine are headers instead of stock manifolds.

 

[Wildman]

Mulling over how to design engine mounts... I'm tempted to cut off the last 2" of the stock mounts and use them as a foundation to build off. I want to get the transmission support in first so I can level the engine since it's leaning a little bit.

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By lean are you talking side to side or front to back? I don't know if it matters on new engines but there was a small amount of slope on the engine from front to back on older models. Even the Dodge magnum V-8 has like 4*-6* of slope.

For you steering pushing I melted mine so I decided to give this steering shaft from Red Rock 4WD. I've got it ordered and it should be arriving soon.

Red Rock Offroad :: Hemi Swaps :: Lift Kits :: Tires. TJ/LJ Skinny Steering Kit (redrock4wd.com)

I'll post some pictures of it and what my impression of it is once it arrives.

 

[toximus]

By lean are you talking side to side or front to back? I don't know if it matters on new engines but there was a small amount of slope on the engine from front to back on older models. Even the Dodge magnum V-8 has like 4*-6* of slope.

For you steering pushing I melted mine so I decided to give this steering shaft from Red Rock 4WD. I've got it ordered and it should be arriving soon.

Red Rock Offroad :: Hemi Swaps :: Lift Kits :: Tires. TJ/LJ Skinny Steering Kit (redrock4wd.com)

I'll post some pictures of it and what my impression of it is once it arrives.

There's 4-5* of slope — nose up. But the left side is also hanging lower than the right side with the Atlas hanging.

I wish they actually had a picture of what that steering kit includes...

 

[Wildman]

There's 4-5* of slope — nose up. But the left side is also hanging lower than the right side with the Atlas hanging.

I wish they actually had a picture of what that steering kit includes...

Got it.

Yes they don't explain much about what is there. But the price was actually cheaper then buying a new lower shaft so I didn't see any reason not to give it a shot. They charged my cc last week so I should be getting it soon. As soon as it gets here I'll post pictures on my thread & I'll let you know what's in it.