6.0L LS swap - adapter decision time (1 Viewer)

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Hi All,

I'm in the process of doing a 6.0L LQ9 LSx engine into my '78 FJ40 and the motor work is nearly complete, so it's time to make an adapter decision and start ordering parts.

My setup:

'78 FJ40 (25 years of ownership :) )
Currently running a 2FE/H55F/Split Case with 4:1 gears and t-case drum parking brake
Full float rear (FJ45)
Longs up front
DC driveshaft out back
Sprung over on pretty flat springs.
FJ55 springs out back for increased wheelbase.
Custom propellor style crossmember, which actually doesn't leak and is really strong. Utilizes rubber "hockey pucks" on the frame mounts for some flex.

Mark's 4WD adapter - This is the way I'd really like to go.
I am running a custom built skid plate which also hosts a traction bar mount. It's built specifically to be strong and only drops below the frame as little as possible to clear the split case.
I solicited some advice from a trusted LC Professional, and this was not his recommended path.
This option is more expensive, but would allow me to keep my custom skid and crossmember, without modification
This option would not require driveshaft mods
This option would not require shifter relocation (transmission and tcase twin sticks)
This option is obviously more expensive

Advanced Adapters:
Recommended by trusted LC Professional
Requires moving drivetrain ~3.5" forward
Requires driveshaft, shifter, crossmember and skid plate mods (if I can even make the skid work)
Less expensive

I think I've read every thread available that touches on the subject, so I'm soliciting more input from anyone who has debated. I'd also LOVE to hear from anyone with some runtime on Mark's adapter with an LS and H55F or 4-speed Toyota. I'm not really sure why this was not the recommended approach, but I plan to reach back out to my advisor for clarification. If anyone has lessons learned or any cost-saving tips on either setup, would love to hear it.

Thanks in advance!

:beer: Ramon
 

DangerNoodle

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No experience with the LSx swaps, but, with the amount of work that Mark's adapter would save you, I'm not sure why you wouldn't go that way. I'd wager that the costs would likely balance out, or even tip in the favor of Mark's adapter after you add in the cost of getting driveshafts redone, steel, paint, and anything else that you would end up needing to modify if you went the AA route. It looks like Mark's kit is cheaper on their site than on AA's. I'd also take into consideration how valuable your time is, or a shop's time, and how much you think that the kit is worth that will save you the most time.
 
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No experience with the LSx swaps, but, with the amount of work that Mark's adapter would save you, I'm not sure why you wouldn't go that way. I'd wager that the costs would likely balance out, or even tip in the favor of Mark's adapter after you add in the cost of getting driveshafts redone, steel, paint, and anything else that you would end up needing to modify if you went the AA route. It looks like Mark's kit is cheaper on their site than on AA's. I'd also take into consideration how valuable your time is, or a shop's time, and how much you think that the kit is worth that will save you the most time.

That's exactly my line of thinking. My main question at this point is around serviceability, reliability, actual experiences - etc etc. Hoping to hear about any hidden drawbacks or other considerations that I'm missing at this point.

Thanks for the thoughtful reply!
 

pjohnson

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IMO, engine placement for proper fan/radiator clearance and cooling behind the engine should drive the decision on which adapter to use. To keep everything in the drivetrain in it's same location means the engine will sit back against the firewall. Probably why your LC Professional didn't recommend Marks.

The Hardcore section may have more guys who have done this swap.
 
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Did your advisor say anything about engine placement? You want the heads off the fire wall in order provide “prop wash” over the hole engine. Perhaps your advisor is thinking the AA unit pushes the engine forward more?
 
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IMO, engine placement for proper fan/radiator clearance and cooling behind the engine should drive the decision on which adapter to use. To keep everything in the drivetrain in it's same location means the engine will sit back against the firewall. Probably why your LC Professional didn't recommend Marks.

The Hardcore section may have more guys who have done this swap.

I'm going to be running electric fans, so hopefully there will be plenty of room and fan to shroud depth won't dictate. Thanks for the input!

Did your advisor say anything about engine placement? You want the heads off the fire wall in order provide “prop wash” over the hole engine. Perhaps your advisor is thinking the AA unit pushes the engine forward more?

Yeah, I really need to call him and get clarification. Sorry to not have all my ducks in a row before posting. I really was hoping to get some varying opinions and reasoning to add to all of that and this is a perfect example of what I'm seeking, so thanks. Before I order anything, I plan to yanke the 2FE and just look at the placement a bit and do some more head scratching :)
 

jim land

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I think you can use a ranger torque splitter to keep your drivetrain at the same location , the engine is pushed forward because the box is between the bellhousing and trans , it locate the engine just right for clearence
 

DangerNoodle

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Why would the AA adapter require moving the drivetrain 3.5" forward?

It looks like the Mark's adapter extends the bellhousing and the input shaft vs replacing the bellhousing. You need to push the V8s forwards to give them space to breathe and that moves the entire drivetrain forward.
 

pjohnson

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It looks like the Mark's adapter extends the bellhousing and the input shaft vs replacing the bellhousing. You need to push the V8s forwards to give them space to breathe and that moves the entire drivetrain forward.
If it extends the bell housing forward, it may place the engine in the proper location.
Which then makes it a pretty good option. Hmm... 🤔
 
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It looks like the Mark's adapter extends the bellhousing and the input shaft vs replacing the bellhousing. You need to push the V8s forwards to give them space to breathe and that moves the entire drivetrain forward.
I've not seen anything about the "space to breathe" being the factor for the placement. I've assumed, maybe incorrectly, that both scenarios put the engine about as far rearward as possible, basically right against the firewall - however the I6 slides back into the recess in the center of the firewall and the V8 heads won't allow the same. I know mechanical fans will dictate moving it forward to work well with the shroud, but from how I understand it there's an ~3.5" difference from a F engine in how far back you can place a LS/SBC when placed as far rearward as the firewall will allow.
 
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I think you can use a ranger torque splitter to keep your drivetrain at the same location , the engine is pushed forward because the box is between the bellhousing and trans , it locate the engine just right for clearence

I was really excited about that option when first reading about it, however:
  • Seems it's NLA and used ones didn't pop up in my searches. Seems they sell pretty quickly when available
  • One more failure and service point
  • Lots of reports of the Ranger boxes leaking. I REALLY don't want another leak to worry with.
  • Will parts be available if required 10 years from now (I'm 46 and hoping this will be my last major drivetrain change. I want to drive and enjoy this thing!)
 

Toyoland66

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I thought the Marks adapter had some additional moving parts but after looking at the kit it looks like it’s just a deeper bellhousing and a crankshaft spacer. I don’t see any downside.

Curious, why are you ditching the 2FE?
 
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I thought the Marks adapter had some additional moving parts but after looking at the kit it looks like it’s just a deeper bellhousing and a crankshaft spacer. I don’t see any downside.

Curious, why are you ditching the 2FE?

Because I'm stupid :D

I have the itch for a hot rod, but can't have another car. So this will kind of scratch that itch. I am not looking for speed, but just that V8 rumble and a little fun.

The downside of the Marks kit is the cost and anything I may be missing, hence the thread.
 
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So full disclosure- I get never looked into the AA or Marks adapter. But if your going this far, moving the transmission and transfer aren’t that hard- cutting and welding. Since you’re pulling the engine anyway, you’ll be putting new mounts in for the engine. Driveshafts aren’t massively expensive to modify. Of course, I quibble about the cost of part constantly so what do I know.
Oh and by the way, I pulled a running 1.5f for a 350 that I pulled(running like a champ) for a used LS. There’s no reason for anything. I just like tinkering.
 
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So full disclosure- I get never looked into the AA or Marks adapter. But if your going this far, moving the transmission and transfer aren’t that hard- cutting and welding. Since you’re pulling the engine anyway, you’ll be putting new mounts in for the engine. Driveshafts aren’t massively expensive to modify. Of course, I quibble about the cost of part constantly so what do I know.
Oh and by the way, I pulled a running 1.5f for a 350 that I pulled(running like a champ) for a used LS. There’s no reason for anything. I just like tinkering.
Yeah, so you feel me ;)

"But if your going this far, moving the transmission and transfer aren’t that hard-"
It really is though. It means shifters moving, crossmember moving, and the main thing is I don't think I'll be able to use my trick custom skid with integrated anti-wrap bar. That's several weeks worth of extra fab work. Trying to avoid that unless there's a damn good reason not to.

Appreciate the input!
 

SNLC

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Not exactly the same but I ran a Ramjet to a Ranger OD box to a H42 to a split case. In an FJ60 and I ran it hard. The H42 and split case was fine. H55 seen plenty of v8 and 4BT work as well.

I think you will be fine as long as you don’t try and drive it like a race car all the time. It might eat clutches faster than normal if you are hard on it as well.

Are you going to want to run it down the highway at 75+mph?

Cheers
 

SNLC

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And FYI, you have probably read the thread but we are running the H55/split case behind a 1HDFT with a real nice clutch and flywheel. It is set up for over 25psi, 250rwhp and 600+ftlbs. 70-series FF rear. We picked this combo vs a 4BT/R2.8 H55/split case because it fits, it’s powerful, it works, it’s strong and it’s all Toyota Land Cruiser.

Cheers
 

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