If you are going to use a tire with pretty good traction and you will have an engine with good power, I would guess you need a front spring in the 650 to 700 or 725 range.
I tried to rate my cut down 6041's but it does not safely fit in my spring tester, I need to modify it so the spring does not come flying out!
Hotchkis and Guldstrand say the rate of their spring is in the low 700 lb range depending on how much it is cut.
I plan on using a 650 lb Hyperco street stock spring with 5" id like the stock Camaro spring, and a "hidden adjuster" on top of it to adjust height.
This way I know for sure what rate I have, and adjusting height does not affect the rate and will be predictable. It will make experimenting with spring rates and making ride height changes much easier.
This is the method used by Mark Steilow on the "Thrasher".
The adjuster I show on my web page needs a piece of 5" tube welded to the top and cut with the spring profile in it to move the spacer down in the proper range. There are adjusters available made that way allready.
The spring I will use has a 9.5" free height, so the spacer has to make up the difference.
Carrera and Hal make coil over shock kits for the First gen.
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Chev 350 Can-Am Vintage Racer
[This message has been edited by davidpozzi (edited 10-16-2001).]