I have an 85 iroc that and was wondering what size sway bar end links i needed?

 

IIRC, all of the swaybar endlinks on the thirdgens are the same... year to year and both front and rear.

They're pretty cheap - Rubber ones are like $4 per side, Poly ones are like $20 for both sides.

 

And both rubber and poly (Energy Suspension) available on the shelf at autozone.

 

They have different lengths though like 4 1/4 in or /2 3/8 in.... i got the sway bar with no links so i can measure the old ones.

 

Stock, they were something like 3½" - 3¾".

Most lowered cars need something less, like 2½" or so. Most old cars with sagging springs, as yours is unless you've changed them recently, are like this.

Don't over-think it. It doesn't much matter. Get whatever length makes you sway bar closest to parallel to the ground, with the car sitting normally.