V6 to ls3 Project

**firebirdmo** · 06-19-2010, 07:13 PM

I have a 1999 Firebird 3.8l daily driver and have just got a good deal on a ls3 motor with 0 miles. Its coming with all the pulleys, but i will have to get a ECM and wiring harnest and all that. i was told that the motor will bolt on to my current trans. is that true? Before i buy the engine i also want to know if it will fit into my current base firebird?

**IceeWS6** · 06-19-2010, 09:14 PM

Originally Posted by firebirdmo

I have a 1999 Firebird 3.8l daily driver and have just got a good deal on a ls3 motor with 0 miles. Its coming with all the pulleys, but i will have to get a ECM and wiring harnest and all that. i was told that the motor will bolt on to my current trans. is that true? Before i buy the engine i also want to know if it will fit into my current base firebird?

should fit no problem..

if it does mount to ur tranny (i think it does) it doesnt matter because the v6 trannys will NOT handle the 400+ hp the ls3's put down.

**dav-02ws6-m6** · 06-19-2010, 11:04 PM

Originally Posted by IceeWS6

should fit no problem..

if it does mount to ur tranny (i think it does) it doesnt matter because the v6 trannys will NOT handle the 400+ hp the ls3's put down.

x1 on that. i think you also have to change the differencial and the driveshaft.(but not sure)

**firebirdmo** · 06-20-2010, 02:00 AM

Oh ok. should i look into getting those needed parts such as a transmission from a trans am?

**garygnu65** · 06-20-2010, 07:08 AM

yep

**dav-02ws6-m6** · 06-20-2010, 06:14 PM

to tell you the truth i think is going to end up been more costly doing the change from a v6 to a v8 instead of just getting a stock ls1. just my opinion.

hopefully some of the Veteran Member will shine in to help you out and give you a better idea.

**Wesman** · 06-20-2010, 06:36 PM

Originally Posted by dav-02ws6-m6

to tell you the truth i think is going to end up been more costly doing the change from a v6 to a v8 instead of just getting a stock ls1. just my opinion.

hopefully some of the Veteran Member will shine in to help you out and give you a better idea.

While thats definitely true, he's not just installing a stock LS1 in a V6 car...hes doing an LS3, which is a significantly more powerful engine.

The drivetrain parts you will need will be the transmission and clutch assembly from a V8 equipped car. All 98-02 cars used the same rears, they just had different gearing and V8 cars had limited slip differentials.

**Jager686** · 11-19-2010, 12:58 PM

Originally Posted by firebirdmo

I have a 1999 Firebird 3.8l daily driver and have just got a good deal on a ls3 motor with 0 miles. Its coming with all the pulleys, but i will have to get a ECM and wiring harnest and all that. i was told that the motor will bolt on to my current trans. is that true? Before i buy the engine i also want to know if it will fit into my current base firebird?

i plan on doing the same thing, however mine is a 94 firebird.... need lots of @#$%^@#!! parts. Good thing im a ebay junkie

**Smittro** · 11-19-2010, 03:18 PM

You can use the 3800-II trany (auto only) if it's a car equipt with the auburn (g80) or the 3.42(gu6) rear and the single drive shaft... Car must be a (y87) Camaro, (y3b) rs, or the firebird equivilent.. Same tranny as ls1 cars m30 or better known as the 4l60e..

However, if you're running a base model v6 car with the split drive shaft and the MXO trans you can't.. It will bolt up and it will then die... 5spd? lol don't even try it..

Either way you'll have plenty of sh&t to do for the project..

**Smittro** · 11-19-2010, 03:24 PM

Originally Posted by Wesman

While thats definitely true, he's not just installing a stock LS1 in a V6 car...hes doing an LS3, which is a significantly more powerful engine.

The drivetrain parts you will need will be the transmission and clutch assembly from a V8 equipped car. All 98-02 cars used the same rears, they just had different gearing and V8 cars had limited slip differentials.

I have a y87 one piece shaft and the auburn..

**JRENIGAR** · 11-20-2010, 06:56 AM

Originally Posted by Wesman

While thats definitely true, he's not just installing a stock LS1 in a V6 car...hes doing an LS3, which is a significantly more powerful engine.

The drivetrain parts you will need will be the transmission and clutch assembly from a V8 equipped car. All 98-02 cars used the same rears, they just had different gearing and V8 cars had limited slip differentials.

Exactly...

**redbird555** · 11-20-2010, 02:50 PM

I think it would be a cool swap because a simple bolt on ls3 will still make more hp than a cam only ls1 and wil drive like a stock car. For the ls3 conversion your going to need a new driveshaft and most likely tranny also the front engine cradle has to be changed out for an ls1 one, then you will also need the accessory drive system from an ls1 car also the pcm will need to be changed for an ls1 one, gauge cluster from an ls1 car will be needed, and you will need a cam sensor extension harness knock sensor extension harness and 24x-58x reluctor wheel conversion box because those three things are different on the ls3 than the ls1. other than that you shoulld be ok the rear end willwork from your v6 car you just may not have posi which would not be good with v8 torque.

**Jager686** · 11-22-2010, 12:01 PM

Originally Posted by Smittro

You can use the 3800-II trany (auto only) if it's a car equipt with the auburn (g80) or the 3.42(gu6) rear and the single drive shaft... Car must be a (y87) Camaro, (y3b) rs, or the firebird equivilent.. Same tranny as ls1 cars m30 or better known as the 4l60e..

However, if you're running a base model v6 car with the split drive shaft and the MXO trans you can't.. It will bolt up and it will then die... 5spd? lol don't even try it..

Either way you'll have plenty of sh&t to do for the project..

ha! my 2 pc shaft went to hell, then converted mine to a 1 piece for future engine swap

**Smittro** · 11-22-2010, 12:07 PM

Originally Posted by Jager686

ha! my 2 pc shaft went to hell, then converted mine to a 1 piece for future engine swap

I never understood why GM used a one piece here and a 2 piece there.. Does'nt make any sense to me

It's mechanically retarded..

**Jager686** · 11-22-2010, 12:59 PM

just wondering after looking into the prices of the ls3 vs the L92, has any1 tried with this engine? its like half the price of a ls3 but 22 less hp..

**redbird555** · 11-29-2010, 01:00 PM

the l92 is basically an ls3 with a different intake and vvt. If you use one ity will make the same hp but in order to run your f body pcm and gauges you will need to remove vvt which involves changing the cam, timing cover, lifter and trays so you would also need to add the to the cost of the l92

**Jager686** · 11-30-2010, 02:12 PM

Originally Posted by redbird555

the l92 is basically an ls3 with a different intake and vvt. If you use one ity will make the same hp but in order to run your f body pcm and gauges you will need to remove vvt which involves changing the cam, timing cover, lifter and trays so you would also need to add the to the cost of the l92

Bah! U just wrecked my day, can't find any reasonably price ls3'S...

**redbird555** · 12-02-2010, 08:44 AM

http://www.ls1tech.com/forums/genera...02-f-body.html this a link showing what is all needed for an ls3 swap or l92 swap into a 99-02 ls1 car so basically get what u need for an ls1 swap and then refer to this list

**Smittro** · 12-02-2010, 01:27 PM

Originally Posted by redbird555

http://www.ls1tech.com/forums/genera...02-f-body.html this a link showing what is all needed for an ls3 swap or l92 swap into a 99-02 ls1 car so basically get what u need for an ls1 swap and then refer to this list

Oh boy..

**redbird555** · 12-03-2010, 06:05 AM

lol if you have an ls3 already its not that bad you would just need an injector adaptor harness, reluctor wheel conversion box, cam extension and knock sensor extension harness. and of course a tune when you get the l92. the list starts to get long because of the vvt elimination