This is an engine swap that is at the moment in the pipe dream stage. What all complications is there to work out. Ive already compiled this; cable actuated tb, custom tune, hybrid harness, non-dod cam, motor mount, and a tranny cooler. Any suggestions would be appreciated. Thanks

 

Mebbe a 4t80(standalone controller

 

I would guess the first question would be- why a swap, and why an LS4?

The reason I ask why a swap- is because factory LS4 W bodys are getting rather cheap. Just poking through the local craigslist real quick found GXP grand prixs and LS4 montes from $5800-$9000. If you've got some kind of sentimental attachment to your specific car- I get it; just wanted to ask the question.

The reason I ask why an LS4- is because an L67 would be a way easier swap- and would easily be able to make the power you want. Sure the LS4 would be different, but that's about the only advantage.


I would imagine that like the L67/4t65hd swap- physically mounting it probably wouldn't be too bad. I would imagine that the new engine/trans mounts would likely drop right in. The HD axles- you could likely just build a hybrid of your stock axles and the new axles like all the L67 swap people do.

The hard part is going to be the electrical. I would guess the easiest route would be just to drop in the new engine bay wiring / pcm/tcm, and then strip down your existing engine bay wiring harness to splice in the bare minimum (horns, headlights, any other plugs that don't match up) as needed.

IMO- I wouldn't bother doing a cam and all the other stuff first. Just drop it in stock, and worry about mods later. The last thing you want is a bunch of gremlins that you can't trace back to whether it's a swap issue or a mod issue. Just saw a lot of guys get into bad spots when the L67 swaps first started with all kinds of bugs.

You do know the LS4 comes with a 4t65HD and not a 4t80 right?

 

Actualy working on an l67 swap atm . Already have the 4t65 installed. I know the ls4 uses a 4t65, was thinking a standalone tranny controller would make things a bit easier. Wanting to do the swap just because, im kindof a knuckle dragger. Ls4 would kinda b a big block for my 97. (Other car is 86 cutlass with a 454.) If i swapped to an ls4 i would eventually go turbo. Finally, another reason for the swap is people told me it cant b done.(like the 02 gp hud, 01 regal rack, and 86 monte ss wheel currently in my 97) btw your l67 swap thread was what inspired me to work on sc 3.8 swapping my car. Printed it off mymonte.com, its in my cars build folder, it was a well thought out how to

 

Thanks- appreciate the feedback. Sure has been a long time

Good luck on your swap!

 

Quick question, you kept referring to a gtp pcm in that thread, did you have to program it to work in the monte or was it plug and play? Thanks

 

Sorry, hadn't been on in awhile.

It was plug n play. I did change some programming, but nothing that would change compatibility with the car- I only changed things like increased idle speed, new injector values, etc so the car would idle and run well enough to drive across town without needing more tuning first (since I was borrowing a garage from a friend).

 

Working on my LS4 swap into a 5th gen 97 Z34 right now as we speak. I looked into possibly doing a turbo on the 3.4 or doing the L67 swap that bumpin96monte made so famously, but I put everything on the back burner and then I decided I wanted that V8 sound more than anything; And I wanted it in something no one would expect. I have sentimental value in my Monte. My very first car was stolen and torched so naturally I am very protective of my Monte because it was my second car and I was in love with the body style.

Back to the swap info: I found the best way to do the swap is to buy the entire LS4 car from www.copart.com. After months of bidding I finally won a 2008 Impala SS for $1500. You can spend that much alone on a high mileage LS4 from eBay. Good luck finding the transmission anywhere. I lucked out with the car. Powertrain still intact except the hit pulled the right axle plum out of the trans with no damage. Needless to say it didn't come with the car; nor did the entire right front suspension. The plus side to buying the entire car (75,000 orig miles) is that I can now swap everything over as needed (including the leather SS interior) and sell what I don't use. Doors for $400 a pop. Glass, tailights, trunk lid, fuel tank, sunroof, undeployed airbags ($$) - the list goes on. I tallied up that list and can make $2800 in parts alone. That pays for the car and gives me build money for my project. I have everything needed for the swap.

As far as mods go, I have been on the fence about what to do. I want a streetable car that sounds nasty. For that, you need a cam upgrade (I was thinking 269LR HR12 from Comp) but then you need to change lifters (which disables DoD) and springs (dual springs, retainers, seats, etc). You will also have to buy a new timing set because you're going from a 1-bolt cam to a 3-bolt cam. Or you can just change the gear to GM 3-bolt 4x/58x and keep the old chain.

On the other side of the fence is just upgrading the rockers from 1.7 to Crane or equiv. 1.8. This will give approx. 20 HP increase and be a moderately pricey mod that would allow me to keep DoD. But the aggressive lope I want wouldn't be quite there.

Either way I have already bought the intake upgrade to LS2 because the LS4 suffers from air restriction. TB, MAF, and injectors to LS2 as well. Found OBX LS4 headers on ebay that look comparable to Doug Thorley at a fraction of the cost: $500.

Final purchase is the HPTuners kit. This is a must especially when changing MAF and injectors. All the tables have to be reflashed otherwise the computer doesn't know anything has changed.

Mounting the power train to the cradle shouldn't be too hard. I've seen this LS4 put in a 90's Impala w-body and, dare I mention on this forum, all the Fieros too. If you want some good info on LS4 swaps look at fieroguru's build. Blow your mind.