Will a fox body 8.8" rear fit in a 1978 fairmont, it has a triangulated four link that is similar to the mustangs but im not sure of the exact dimensions and bolt holes lining up. If anyone knows please let me know.  

Yes, if it is from a Mustang, it should be a bolt in affair. The 79-up  Mustang was developed from the Fairmont chassis, so it should work. Do some measuring before you plunk down yer cash though, just to be sure. Perhaps some of the Ford fellows here would care to comment. Good luck with your project!
 

thank you for your help and opinion

FORD GRANADA,FORD MAVERICK,9INCH SHOULD FIT RIGHT IN,FIRST MEASURE YOUR REAR END FROM BACKER PLATE TO BACKER PLATE,HIT THE JUNK YARD WITH YOUR TAPE MEASURE TO BE SURE ON YOUR FIGURES...GET BACK WITH YOUR MEASUREMENT AND I WILL LOOKUP THE GRANADA AND MAVERICK FIGURES FOR YOU,YOU MAY NEED TO CHANGE YOUR SPRING SETUP.

ALSO THE INFO YOU GOT ABOUT THE FOX BODY MUSTANGS WAS GOOD INFO

DAVE(SIDEOILER)

I would really like to keep the car a stock triangulated four link but thank you for your input anyway  

Plenty of folks are going quick and fast with Fox four-link rear suspensions.  Still,  I'd strongly suggest adding a panhard bar for street/open track use and a drag-style anti-roll bar for serious strip duty (several suppliers in the Mustang world for each).