Hay folks , looking to put Hiviz sights on my p320 . Hiviz is closed till after new year so I can't get info . On there sight they have sight # 6 and #8 and it seems to me neither will fit . Does any one know anyone know about this ? Do they have sights that will fit ?

P320's seem to come with both #6 or #8 front sights.

You'll have to determine which your gun has, or needs, depending on your POI.

Caliber also makes a difference.

Not sure what you mean by "neither will fit"?
At any rate, my P320 was shooting waaay too low, so I changed my front sight out to an 8, which corrected the matter.
And BTW, mine got shipped back to Sig yesterday for the now infamous trigger upgrade.