Its a lot of work but some combinations run better with the cam set advanced or retarded from standard. A mechanic at the local performance shop told me he bought a healthy 305 (just overhauled) very right because the owner had tried everything and the engine was a slug so he replaced it. The vacuum test showed very low for a healthy engine. The mechanic cam-timed it and found a lot of power and healthy vacuum. There are several ways to do this but he ran cold compression checks on several cylinders, then moved the cam forward and back tooth by tooth on the timing chain to maximize the compression readings.
The other method is to use a degree wheel on the crank and a dial indicator on the rocker arm to dial it in but I don't know the details.