Hi guys,
I'm starting to dig into what options are available for swapping in a Gen5 LTx motor/driveline into my 87 IROC and I see a few different options. It's either going to be a 5.3L or a 6.2L with an 8L90 so we will see how that goes. I'm not looking to change out the k-member from the stock unit unless I really have to so it looks like Holley/Blackheart has some LTx mounts that adapt the stock pads to fit their clamshell mounts? I'm having a hard time finding the rest of the info though on those...

I will also probably run the Holley swap pan and accessory front kit with locates the A/C compressor up top, assuming that's what it takes to clear the factory front crossmember and steering?

Thanks for any help, searching on the forum isn't working all that great for whatever reason.

 

Do you have a Camaro or a Firebird? This will likely be easier in a Camaro due to hood clearance, but it’s being done by LSXMatt on YouTube in a Firebird. He has a 6L80 in his, but all the research I’ve done so far says that a 10L fits where an 8L does, and an 8L fits where a 6L does. I am planning on an L83/L84 10 speed swap for my Firebird eventually, so I’ve been looking into it for awhile.

 

It's a Camaro. I'm not worried about hood clearance, it really boils down to engine mounts/crossmembers and the accessories to drive everything. The 10 speed autos are definitely a bit larger than the 8 speeds which is why I'm sticking with the 8 and trying to make that fit.

 

Hawk's has a few things they claim are specifically for Gev V LTX, and I do see specific 8L90 parts too. I can't vouch for function, but they do have them.

 

I have seen this said, but haven't seen many dimensions to indicate that. Do you have any resources for the case size on these things? I would stay with an 8, but I've heard they have issues.

 

Ahh I see those. I think I will give them a call on Monday and see what they are built around as far as the k-member goes and where it places the motor.

Exact dimensions, no. But we had one laying around at the shop and it just so happened to be sitting next to an 8L90 and it looked taller and fatter to my eyes. The 8L90 transmissions are great, very few have actually had issues (more so converter problems but that's also overblown) and they consistently hold 800-900 rwhp.

 

Through the highly scientific method of... overlaying and resizing two pictures... I didn't see much of a difference. Notably, the angle of the two transmissions is off a little, but without the heat shield, I thought they were near exact.

Blue 8L90 superimposed on Grey 10L80.

 

Report back what you find! I haven't gotten to that stage yet, but would like to know as well.

 

Since I already made one, here is a 10L80, 6L80 comparison. Use at your own risk any future readers. I made both of these in minutes playing fast and loose. Just a scale lock and dragging it as close as I could align it.

Red 6L80 superimposed on Grey 10L80

 

Why do you want to use an 8L90? I have it on good authority that those things are hot dog-sh*t.

Wouldn't a 6LXX be cheaper?

 

We've been tuning and racing the 8L90 since it came out and they are solid and can hold 800-900 rwhp pretty reliably. I absolutely despise the 6L80/90s and wouldn't put one in there if it was free, and that's based off of tuning and racing them since they came out in 2006.

 

did you hear much back from Hawk’s? Excited to hear how it went. I put together a more thorough thread on transmission size comparisons over in the Transmissions tech board last weekend.

 

Got sidetracked with other projects but my goal is to give them a call tomorrow.

 

Any updates on this? I put a 2017 LT1 with TR6060 six speed in my 88 camaro. Lots of crap I had to do but it works and works well. I can provide any advice that may help.

 

I need to stop spending money on other stuff. LOL My problem is that I have too many other cars that I'm doing stuff to and just when I think I'm done with it something pops up. I did have to replace the fuel pump this past week in the IROC because the original fuel sock on the pickup just disintegrated and it made it's way into the pump and smoked it. Also ended up replacing the shocks and sway bar bushings and end links because they were original and crusty but it's up and running again.

I did call Hawks and get information on their LTx swap parts and it sounds like it may be the way to go. They said you have to modify the box on the back side of the compartment otherwise the covers, etc hit it but it doesn't sound bad. My game plan is to actually order the parts here in the next couple of weeks to just start collecting things for whenever I can get around to this project.

What did you end up doing with your swap? What mounts, etc did you end up using and what accessory drive did you use?

 

I know what you mean about being busy doing other things. I did a lot of work on my camaro but ran into vibration issues with the drive train. I had modified the transmission with a previous generation of rear case but that caused vibration. That ended up stopping any work for a few years. I finally started to work on the car again to get it running again. Putting the original rear case back on and modifying the rear case to fit the shifter and motor mount solved the vibration issues.

I used Dirty Dingo Adjustable mounts https://www.dirtydingo.com/shop/index.php?cPath=392_402
I used this crossmember since it has the torque arm attachment: https://www.holley.com/products/engi...ts/71222005HKR
I used this accessory drive: https://www.holley.com/products/engi...s/parts/20-170

 

Here's the post I did when I was really into working on the car:

https://www.thirdgen.org/forums/ltx-...1-install.html

 

I'm wondering how the Dirty Dingo adjustable mounts compare height and position wise to the Hawks swap mounts. I would think being non-adjustable they would make things sit a little bit lower but that's purely a guess.
I think the Hawks crossmember also has the torque arm attachment built in, otherwise I don't know where it would go as I plan to use an 8L90 in this application.

 

I have no issues with height with the dirty dingo mounts. I just looked at the Hawks crossmembers. I don't see a torque arm mount. I know some people have mounted torque arms to the body but I didn't want to go that route. To use the holley crossmember, the is a mount adapter I had to use. It has offset bolt holes on each side. I can remember where I got it yet.

 

I found the trans mount adapter but it says for TR6060 only.

 

How much experience do you have with the 8L90?

I work for a GM store and let me tell you, they've been miserable to deal with from a reliability standpoint. The 17 and later are better from an internal component standpoint, but they all suffer from the same shift/driveability quality issues

 

Aww crap, I mean it's definitely going to need the torque arm mount integrated into the crossmember especially with a transmission like the 8L90. I am going to call them back and ask them about that part... otherwise I would have to adapt the Holley crossmember and just make it work with the 8L90.

 

I've been tuning and racing them since they came out. Sure some of them can have some driveability quirks but they are generally a very good strong transmission and have taken 900 rwhp pretty regularly. I honestly would love to put the 10 speed in instead just because it is a better transmission but I just don't think it's going to fit based on the measurements I've seen.

 

Finally found a good deal on a 6.2L along with a 10L80, so looks like I'm going that direction now. Guess I'm going to find out how much clearance is required for this transmission after all.

I've got the mounts and trans crossmember from Hawks along with their long tubes and y-pipe for the swap. I also ordered the Hawks subframes and torque arm to get it off of the tail shaft of the trans and it will be mounted securely to the subframes that way.

I also ended up ordering the Holley mid-mount accessory drive kit to have as much clearance as possible, certainly not cheap but from everything I've read is by far the nicest kit.

Lastly I ordered up a PSI Conversions swap harness and I already had the ECM and TCM from the pullout engine/trans so I should be good to go there. I'm going to try to make the CTS-V pedal fit and it looks easier to make a mount for than the other options.

I still haven't figured out what I want to do about the dash and gauges, figure I will start investigating that here shortly but I would really like to keep the factory gauges if possible. I have seen some conversion boxes to take the OBDII data and output standard signals for analog gauges but maybe I will just do a new cluster of some sorts.

 

Well would you look at that, the 10L80 transmission fits! I didn't have to even pound anything to make room, it's a bit tight up top but clears with an inch or two to spare. The trans pan is the lowest point right now but it's not bad, about as low as the torque arm mount that goes to the subframes. Actually, I'm going to start a new thread with a lot more pictures and details here in the next day or two but just wanted to update this one.

 

You’re a hero NicD! Very nice pictures and insight confirming that it can be done.

Exciting stuff and good work!