Differential Question for a sonoma

i have a 99 GMC Sonoma with the 4.3 V6. i ordered my suicide 3 link today and they asked me if i had the 7.5 or the 8.5 in differential cover. how do i tell the difference. i tried measuring it, but its like 11 in side to side. is there a way to measure it???

if it helps any...the cover has a pointed look to it to the left of the center of the cover plate???

i think they are talking about the gearing

is it round or oval? Round is 8.5, oval is 7.5
Newer S-series had the option of the 8.5. Take a picture and post it. I'm sure on S10forum.com they know the code to tell the difference.

anyone got a pic available of the two styles side by side so i can figure this shit out. ricky from SD told me it was on s10 forums in the tech section, but i cant find the tech section on their site?

bump...

pull your diff cover and measure the ring gear.....

looking at your profile i am gonna say thats a 7.5 housing i may be wrong tho......

DO YOU KNOW YOUR RATIO?? IN 99 ONLY THE 3.08 RATIO CAME WITH A 8.5 INCH RING GEAR