Those are pretty rare to find. Most of the ones of seen at mustang parts stores are about $1,000 for the lower. Even in a mustang graveyard, I'll bet they've all been picked out. Good Luck.
chevy runs deep, Don't step in chevy!
289 - Holley 4150 570cfm; Performer intake; mild cam; MSD HEI; 302 heads; Roller Tips; Hedman Tri-Y headers; H-pipe w/Flowmaster 40's; 9 in posi 3.50; 205/50-17F; 225/50-17R.