Replacing front shocks on 74 el camino, cant get the top nut loose?

i am replacing the coil springs and shocks all around on my 74 el camino, i have managed to gett it all done except for the front left shock. i cannot get the nut at the top to get loose. it is the kind of shock that goes thru the middle of the coil spring. i cant seem to hold the stud or the metal stem tight enough to break the nut loose, i have tried vise grips and used a ton of WD- 40 but it wont come loose. Any help please!!!!