Spring Rates for 2nd Gen Firebird???

[BMR Tech]

I definitely agree that the car needs stiffer front springs and a larger front sway bar to balance the car out. I am surprised that a 350 lb. progressive front spring works at all for a handling application and feel sorry for your bump stops . As shown in the chart below, even OE springs ranged from just under 300 lb/in to just over 400 lb/in. These are all the OE rates from '70-'81:

Until a few years ago, QA1 only offered two spring rates for the Pro Coil kits (what they called small block and big block springs). They were progressive rate and mainly designed for street rods, not really for road handling. They have gotten a little better since then and offer more choices now. All of their springs are now linear wound and they have 4 rates available - 250, 350, 450, and 550 lb. springs. In my opinion, the 550 lb. springs just barely cut it for what you are wanting to do. They would be a huge improvement but I prefer a 600-650lb linear spring unless you are building a dedicated track car. Also a 1.25" solid or 1-3/8" hollow front sway bar should help tame your understeer woes. Your rear sway bar seems a little large. I am not aware of a rear bar that big designed for a second gen F-Body, is it something custom?