How can I improve

[JLM]

Now that I've got some more money to start working on the firebird one of the things I want to get accomplished is the suspension work. The car already has a disc brake kit up front with new PST polygraphite busings. The car is currently sitting on the stock control arms and springs with gas shocks.

I am looking to lower the car slightly (perhaps 1.5" front and 1" back). I'll need to pick a lowering spring up front that can handle the weight of a 455 cubic inch motor that will likely havev a turbo attached to each bank.



In regards to the rear suspension, I plan on a set of modified leafs to lower the car roughly and inch out back. Is there any other components that will help the rear-end keep up with the front end?

[Joe_Rocket]

Hey JLM,

A few questions...

How much are you willing to spend?

What are your overall handling goals?

What size wheels and tries are you planning on running?

I think you'll see if you read a lot of the posts on this site and investigate some of the links to some of the member's own sites, you'll see there is a fair amount of variety.

I'd read David Pozzi's site for starters: http://ourworld.compuserve.com/homepages/David_Pozzi/

Also see what Carl Cassanova has to done:
http://www.geocities.com/casanoc

You could at least go with a set of springs and the guldstrand mod if you are on a budget, or get as wild as a complete bolt in subframe with Vette suspension if you have money to burn.

I didn't want to spend too much, so I have Speed-Tech upper and lower A-arms on my 69 Camaro with adjustable coil-overs. Cost was about $1500 I also went with the Guldstrand mod. These were an upgrade from a "similar to yours" stock arms and PST Polygraphite that I used to run.

Your spring rate up front should in part be determined by what tires you're running, not just the weight. David explains this on his site. The more grip you have, the stiffer a spring you'll need in the corners.

I've heard from a few here, that the poly bushings are not all they're cracked up to be. Polyurethane tends to bind under load. The polygraphite, graphite impregnated urethane, is suposed to be self lubricating and not bind like typical urethane, though I don't know how effective they really are. I was told by some that they'd rather have stock bushings over urethane.

Anyhow, I'm sure you'll get lots of input from the gang here. I'm only repeating what I've picked up from others. The more details you provide, the more we'll all jump in with our thoughts.

[JLM]

Thanks for the info, I'll start by checking out those provided links.

[68Formula]

Just thought I'd let you know my combination. I have a '68 convertible with a 455. I just got the 455 installed as well as the suspension. There are still a few mechanical bugs to work out (including an alignment).

I can tell you on my short initial test drive before the snow flew, the ride was very compliant. Without an alignment I really wasn't in a position to push the handling limits by an means, but it does corner flat.

Here's what I did:
Body Bushings: Comp Engineering Solid Aluminum (stock height)
Upper A-Arms: Detroit Speed
Lower A-Arms: Speed-Tech Performance
Front Springs: NPD C-7412-129
Front Roll Bar: Hotchkis hollow
Front Shocks: KYB GR2
Rear Shocks: Edelbrock IAS
Rear Roll Bar: None
Rear Springs: 5 leaf with polygraphite (next time I would go with del-a-lum)
Tires Front/Rear: 245/45R17 and 275/40R17
Relocated upper A-arms per DSE specifications


Can't wait for Spring! (Actually I can, got a list of fix-its before I can really take it out on a cruise).

Good luck.