My 85 Firebird started out as a base v6. I'm wondering what suspension is different between the v6 and v8 cars? No i didn't see anything in the sticky but I did look.

 

The "suspension" is IDENTICAL IN EVERY WAY.

The "soft" parts (springs, shock, sway bar bushings... kinda like, spark plugs and fuel filters, same concept except different systems of the car) have some variation; but since all that stock crap is totally wore out and busted anyway no matter what the car came as, it's all going in the trash and getting replaced with stuff that fits your current setup.

About the only part that you would keep that's "different" is the sway bars. Those don't wear out so much. 6-cyl stuff tends to be real weeeeeeeeeenie and lightweight, not intended for all-out driving enthusiasm. (else the car wouldn't have been equipped with a 6-cyl in the 1st place, eh???) Those, you would probably want to upgrade.

 

Yeah what sofa said. The 4,6,8 cyl cars all share the same parts on the suspension. The 6cyl cars has softer springs, softer valved shocks, smaller swaybars.

The V8 cars got stronger spring rates, bigger swaybars. Iroc, Z28, trans am GTA got faster ratio steering gear boxes, even stiffer springs/shocks and even larger sway bars

 

IROCs got an extra brace to tie the front frame horns together by bolting in between the sway bar and the body- it's called the "wander bar" and is said to really stiffen up the front of the car.

the later cars were both glued and spot welded together, which made the body overall a lot stiffer than the older cars that were just spot welded. i think they made that change in 1990 or so.

the cars with 16" wheels had different front lower control arms, but the only difference was in where the steering stop was.