Most 85s have problems with the clear coat paint, so if it doesn't, it's
been repainted. If the interior is leather and not a wreck, most likely its
been replaced. The weahter stripping sucks on all years.... However a complete weather stirpping
kit is big $$. If it has a clear top, check it out carefully. GM changed
the material twice since then and the 85s are prone to heat stress cracks
(a million tiny cracks you can see from the inside looking out) that will
turn into real cracks...plus the 85 still has the pin and floating screw
mounts in the front, so only tops from 84-mid 86 will fit without changing
the front mounting brackets and moldings. Be thankful if it has a solid
top. Check the door panels, the material will shrink if the car was left
out on the sun a lot. Same goes for the bumpers...they are prone to warp,
particluarly if it is a dark color. The brakes on the 85 simply suck. No
one makes performance pads or rotors for them either, and upgrading to
larger brakes is expensive and requires custom brackets (which is where
they soak you). Make sure you check the steering after the car has sat for
a while. The racks sometimes get "morning sickness" where they will be
stuck until you work them back and forth for a while...this is a problem
with all years i think...but don't forget the 85 is almost 17 years old.
The 85 came with stock suspension or Z51 optional road race suspension. The
Z51 option came with the 3.07 gear, HD cooling system and an oil
cooler...all good things, but it also comes with stiff springs that ride
like a stage coach, great for road racing, not great for drag racing.
Changing the springs is not that expensive tho...so you might be better off
with all the other stuff that comes with the Z51. Also the 84-87 share the
same suspension geometry, that was changed in 88....therefore the wheel
setback and shocks are differnent than the later years (suspension has less
travel, wheels require less set back). Power windows are very slow...still
use a plastic ribbon that is prone to break. Again new window regulators
are not all that expensive if you look around. My tranny guy told me the
case from the 85 700r is one of the best, but i've heard other opinions,
again keep in mind that the car is 17 years old and if the tranny is
original, you might be rebuilding it shortly. Also as an automatic, it will
have a dana 36. I never had trouble with mine, but you know the drill. That
is about all i can think of off the top of my head.

I hope i didn't scare you away from the 85. Fact is, if you are buying it
as a drag racer, it's a good car and most of the things i pointed out are
true of most C4s and you wouldn't have to address many of its faults. The
85s are lighter than the newer cars and tend to be inexpensive since they
are among the oldest C4s ($7500 is not a bad deal, IF it is in very good
condition and needs nothing). The 85 comes stock with forged TRW pistons
and beefier rods than later years