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Discussion Starter · #1 ·
I am just starting to kick off my project car I aquired, here is what I have and what my plans are. Looking for any good feedback from people who have done this before.

This is a V6 firebird with standard trans. I have already pulled the front end and engine and transmission.

Looking to go back in with this front end

http://www.bmrsuspension.com/?page=products&productid=348&superpro=0

first question I have is I am wanting to put an LS3 in the car, will it bolt to the standard LS mounts on that front end?

Next question is in regards to the axle and read end. I am looking at these as possible replacements

http://www.spohn.net/shop/1998-2002-GM-F-Body/Drivetrain/Strange-Engineering-12-Bolt-Rear/Strange-Engineering-12-Bolt-Rear-Complete.html

http://www.spohn.net/shop/1998-2002-GM-F-Body/Drivetrain/Top-Gun-Driveshafts/Top-Gun-Driveshaft-Stock-Transmission.html

http://www.bmrsuspension.com/?page=products&productid=1398&superpro=0

http://www.bmrsuspension.com/?page=products&productid=316&superpro=0

In regards to the LS3, I already got rid of the ECM and harness with the V6, so will a LS1 wiring harness work on the LS3? and I plan on getting the ECM with the motor and transmission, what challanges will I have getting that hooked up to the dash?

Thanks in advance, if anyone see's a part im looking at that isnt a fit please let me know
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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Is the trans going to be auto or manual?

What kind of modifications are you planning to the LS3?

How do you plan to use the car - stoplight drags, 1/4-mile track, auto-X, road racing? Or just a sunny day cruiser?

No matter what you are doing, but particularly in light of the power handling capabilities of the driveshaft and rear, you don't want that trans mounted, non-adjustable torque arm. You want a chassis mount, adjustable, Personally, if you are going with Spohn on the DS and rear, I would get his torque arm, tubular K-member, and see if you can cut a package deal discount.
 

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Discussion Starter · #3 ·
Ahh thanks for the feedback.

I wont be taking it to the track or anything like that, will really be just to take out in nice weather and have a little fun. So I dont want to go too over the top, but I want it to drive right and was told the factory rear end is horrible, so thats why im looking at the improved subframe.

I will go standard transmission, if I were to put an automatic transmission on that I would have to learn how to kick myself.

on the LS3 not really sure what mods if any ill look at, this is my first project car and im pretty green. So if you have suggestions around that let me know

Right now im in the gutting process so I can get it off to paint. The engine compartment has a little rust, and if im going back in with all new stuff I want the engine compartment spotless.

Looking to use willwood breaks on it and all that good stuff.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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The LS1 motor mounts will work. While the LS3 engine is dimensionally very similar, they did relocate some of the sensors. Best bet would probably be an LS1 harness, with extensions for some of the sensors. Using the LS1 harness should reduce or eliminate issues with interfacing with the 99 body connectors. Not sure which PCM to use. Not sure if an F-Body LS1 accessory bracket will work?

Not sure, but I suspect the LS3 will have an electronic throttle body. You would have to use a mechanical TB off an F-Body LS1.

The Corvette LS3 was 430 HP. You are looking at a rear axle assembly that can easily support 750-800 HP with the right options. I have the Strange 12-bolt with high strength limited slip unit behind my 800 HP / 800 lb-ft nitroused LT1. You do realize that the $2,040 version is not for a street car. That includes "spool", not a differential. You will need the Eaton posi.

I've pretty much reached my limit of knowledge on the LS1/LS3. I'll send you a PM with a suggestion for an alternative source of more info.
 
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