3rd gear grind!!!!!

so i went to the track and ive been running mid to high 15’s but it sucks because my 3rd gear grinds!!:bang: the only way i can not grind is if i take longer to shift. could it be my shift linkage, tranny mount, or somthing?? this sucks!!! im trying to haul ass and then grind into 3rd gear! im pretty sure i can run a faster time if i can fix this. is there a way to adjust the clutch cable??? i dont know but i need help please

synchros… can bandaid them with GM synchromesh fluid or royal purple fluid otherwise have to replace them