Suspension 1997 Firebird

Will try that route-may be able to find springs from the salvage yard.

We are researching increasing spring rates (a lot more than you will be) due to the extra 400#'s of Chrysler flathead drivetrain we put in there.  I have the spec's somewhere on the stock springs and Moog has a spring guide where you can filter things like length, weight, diameter and end type https://www.moog-suspension-parts.com/u … prings.asp.  Start with weight (probably the same as the V8), diameter and then end type.  Odds are you can find one about 1-2" shorted but a heavier spring rate.  Then use the MOOG part number on Rockauto.  On Rockauto your can then find out the application of that spring and look for cheaper or used alternatives.

Stock spec's that matter are: 3.36 ID, 14.88 free, 10 compressed, stock 223#/in with one end "tangential" and one a pigtail.

One thing slightly more important is brakes by the way.  They are totally budget exempt so you could go nuts or you could just rebuild what is there.  FYI, even in the Heartbeat of America, ain't no one stocks the wheel cylinders for the rear drums...either upgrade to the V8 discs or carry at least one spare.

Thank you for the replies.   We have removed a large amount of weight and the car is sitting higher-removed the entire rear hatch, moved the battery to where the rear seats were located, removed the entire AC system and condenser, removed the front nose clip since it was damaged in the collision and built new nose out of aluminum. Removed power windows and T tops, removed the dash.  Since the car is so much lighter , that changes the needed spring rate-I wonder if we would be better off cutting the existing springs and adding Bilstein shocks?  Also will remove the rubber rear isolater that the coils sit into and use the heater hose mod.   Since the car is so much lighter than a Z28, it might sit to high with z28 coils.  If I lower the rear quite a bit, the track bar could be cut and Re-welded for the right length.  I bought C5 corvette brackets and will put on front z06 brakes.  The rears are already discs.

Don't forget, you'll gain a good bit of weight back once you cage it.  Also, about the weight of the drivetrains, I don't know that a 3800/4L60E would really be any lighter than an LT1/T56.  I'd definitely think either LS1 drivetrain would be lighter.  This is just conjecture, but, I think a 3800/4L60E combo (what your car came equipped for, even if you've switched it out for a T5 now) would be one of the heavier 4th gen drivetrain options.  V8 springs would still likely be stiffer though, just because of the performance. 

On the braking front, so, we upgraded the Buick to the same brakes as a '93-'97 F-body uses.  With a set of Raybestos ST45 brakes up front (and a crappy pair of drums out back), our car had ridiculously good braking.  Easily the best aspect of the car, dynamically.  Believe it or not, the Century is lighter than the Firebird from the factory.  I don't think we've lost anywhere near as much weight as you, but, they're probably in the same ballpark.  Of course, a RWD, 5MT car with +40hp on a FWD, 4AT will carry more speed, but, don't feel like you absolutely have to dump a huge pile of money into brakes for your first race.  That setup with a good pair of cooling ducts (also much easier/more effective on a RWD car) provided fade-free braking for our entire race.  We did use extremely good brake fluid though (Motul RBF 660).  I'm sure we'll want to upgrade our brakes at some point, but, it's very, very low on the list right now.

we put our battery in the rear pass side floor board. The rear Bilsteins aren't to bad the front struts are a few $$$ but worth it. Just make it safe and dependable for your 1st race, then work on making it faster.