I've been reading/searching this forum but unable to find my answer. I've found a cheap wrecked 2008 Pontiac G8 Gt with the LS3 engine and auto tranny (6L80 I believe). Will this be a fairly easy swap or am I looking at a long and arduous battle? I'm looking for the answers to the typical questions of clearances, wiring, tranny mounts, etc... I'm guessing the engine will mount up fairly easily, it's the other stuff I'm wondering about. Any help would be greatly appreciated!

It would probably be just like any other LSX(LS1, LS2, LS3, LS6, LS7, LS9, and the newer truck motors) swap. Biggest problem would be a lot of wiring. Get the motor, tranny, computer, and probably the whole harness or get a custom harness made.

I can tell you right now, long and ardous battle, but it'd DEFINITELY be worth it to have probably the only LS3 Third Gen in the world. Clearance should not be an issue at all with the engine, with it being a small block, it may mount up close to the original engine mount spots. The transmission looks like it'd have clearance, I googled it! I'm about 100% sure that mounts for it would have to be custom made. As far as wiring goes, that'd have to be custom, or modified also. You'd most likely need a new LS3 controller kit too, if you're getting just a bare engine. But if you're pulling it yourself and know what to grab, it's all good.

I'd be buying the entire car. It's been hit in the passenger side door, but the motor, tranny, etc is all good. The car only has 18k miles on it.

Just a thought- I guess my 700r4 tranny will bolt up to the LS3 right? I'd have it built to handle the power, but it could work.

OH NO! Don't use the 700R4. The 6L80E is a lot stronger transmission.

This is what 6L80E means; it's a 6 speed automatic, longitude (RWD), 80 is the strength which is the strongest GM has from the factory, and E is electric.

The 700R4 is basicly a non-electric 4L60. Most people might said that the 700R4 is weak.

Plus those 6L80E are expensive over $3,000. If you use the computer from the G8, you'll be able to control the motor and the tranny.

Here's the gearing for the 700

* First - 3.059
* Second - 1.625
* Third - 1.000
* Fourth - 0.696
* Reverse - 2.294

Here is the gearing for 6L80E

1 2 3 4 5 6 R
4.027 2.364 1.532 1.152 0.852 0.667 3.064

Here's more info on a brand new one.

http://www.bowtieoverdrives.com/cata...php?ITEMID=696

http://www.gmtuners.com/
http://www.speartech.com/

your gonna need a 4th gen oil pan, and maybe the front accs, and your exhaust is gonna need the exhaust from a 4th gen or headers from hawksthirdgenresource.com. Motor mounts from your small block with some motor mount adapters. Your going to get a torque arm from an aftermarket, go with a shorter one like a Jegster since that 6 speed needs a bigger yoke wit ha fabbed driveshaft, fabbed tranny mount. Lots of work but with your car being pretty light you may see over 30 mpg, you would have a fun driving car that wont kill ya finacially especially if your doing it all your self. Some of this has been done to death far as the motor is concerned, but those trannys havent been used much yet so they are still pretty new. Have fun.

You'd have better luck posting in the proper section... there is a subforum specifically for LSx/LTx swaps. There are a couple people swapping LS3s into their Thirdgens that have created posts in that section. The transmission will be the big question for you, though you might want to consider just selling it (if it is worth 3k) and buying a built 4L60E/4L80E.

If its a GT model, its not the LS3 (only found in the GXP). What you'd actually be getting is the L76; still not a bad motor by any means.

The swap will be like just about any other LSx series motor. Make sure to grab the wiring (as much as possible), ECU, trans (6 speed auto? yes please ).

Have fun and take lots of pics.

LS3 swaps are great. In most respects very similar to any LSX type swap... I used a GMPP LS376/480 version of the LS3 and it works great...

http://www.thirdgen.org/techboard/lt...gine-swap.html (LS3 Engine Swap)

Holy cr-ap is it actually posibble to swap in a 6 speed automatic?!?! Like... the one from the LS7 corvette? With an LS7 for example?

The trans in a C6 vette I believe is mounted in the rear like a transaxle assembly. It is completely different from a traditional trans like you'd see in an fbody.

C5 and C6 transmissions are rear mounted and directly bolted to the rear differential. Its almost a transaxle and if they were, kit car guys would be all over them as cheaper and more plentiful options to Porsche/Audi units

The v8 G8s do have 6-speed autos. I believe the new camaro does as well. Nothing funky like the vettes, not sure what you're looking at for crossmember/driveshaft work though.

i'd buy a 6 speed auto in a heartbeat for my car... didn't even knwo it was possible... i can imagine the shifter plate on the interior would have to be modified as well.. for sure you'd need shorter tq arm, driveshaft, and a custom crossmember as well. An aftermarket 6 speed auto swap package should be available to replace the 700r4!

I don't think it will be very easy at the moment if you don't have the ecu, wiring, etc. These transmissions are computer controlled and fairly new to market. I do have to say I like having a 5sp auto in my v6 G8, not to mention being able to select auto, sport shift auto (a bit more aggressive), and manual gear selection. Having all this in a 3rd gen w/ six gears I'd think would be heaven

This place says they have done it, but I'm not sure if they have a stand alone controller.

http://www.speartech.com/

Yes, I am doing a similar swap from wrecked 2010 camaro ss L99 A6 into my 91' RS and speartech is building the harness for me. I send him the one from my car and the 10' camaro, and the ECU and $1300 and i get a complete plug and play harness, and can use the electric throttle body. Call Speartech, they are the only people that can help you, i have researsched the poop out of this and they are the only game in town!!!

Ehhh. Not so, sir. There are a few other companies that make custom LS harnesses for conversions and hybrids. Painless is one, and I believe ls1wiringharness.com is another. Or you can even send the 3rd gen and LS harness to Hawks and they can make one for you too.

Or there are a few members on here who may do it for a price, like Pocket

Its a L76 and its a DOD motor, so if you want to upgrade it, you gotta do a little changin in the motor.

If you guys are thinking of using 6L series transmissions, you better be prepared to be cutting your trans tunnel apart.

the 6L series hydramatic transmissions are MUCH larger in the *** end then a 700R or 4L. You'll at the very min need to bash teh tunnel, but more then likely need to cut the tunnel and lift a portion of it up to clear the back of the trans.

The T56 fits perfectly in the transmission tunnel and it's a 6 speed... Is the auto 6 speed really that much bigger than the t56?

Yes.

there was a good thread, i think over on ls1tech maybe, a guy was putting the ls3/6l80e into an old stingray, and they documented the size of the trans is very large, much larger than a t56 behind the bellhousing. i'll look for the thread, but it pretty much boiled down to you will cut off the tunnel and raise it or that trans will not fit at all. however, if i had the donor and a third gen, i'd be all over that swap. it may not be easy, but it'll be pretty sweet when its done.

Hawks Yes, Painless, NO!