There’s not a short answer for this.  You say a stock rebuild but do not mention if this is the original camshaft or a replacement.  Many factory camshafts have an amount of advance built into them.  On the flip side of this, manufacturing variances in both the camshaft and the timing chain sets can have the camshaft off significantly even when installing it with the timing set with the dots on the Ford Y positioned 12 pins apart.  Unless you actually degree the camshaft in with a dial indicator and some form of degree wheel, you will not know if the camshaft is installed where it belongs.  The worst case I’ve seen was just recently with a 351W where the camshaft was 21° degrees off.  That particular camshaft required that the timing set be installed a full tooth off and then the lower multi-slotted sprocket used to fine tune the camshaft timing.

Advancing the camshaft 4-6° as measured in crankshaft degrees is the normal amount to install a camshaft with a new timing chain set for most street drivers.  This ensures that the camshaft has room to retard as the timing chain stretches over time.  Advancing the camshaft beyond just installing it ‘straight up’ increases the manifold vacuum at idle, helps with low-end throttle response, an improved signal at the carburetor, and overall drivability.  For clarification, ‘straight up’ is not just installing it with 12 pins between the marks but where both the intake and exhaust lobe centerlines measure the same.  You only know that by degreeing in the camshaft.  Advancing the camshaft will shorten up the intake lobe centerline number and increase the exhaust lobe centerline number.  The number of degrees that the camshaft is actually ground on is not changing but moving the camshaft directionally one way or another away from the as ground lobe centerline number does affect the aforementioned reasons for advancing or retarding the camshaft.

It’s important that the camshaft be degreed in and not just assuming that the cam is going to advance as desired based on the various slots at the crankshaft gear.  I typically order the camshafts with 2° of cam advance built in which is 4° as measured at the crankshaft.  Even with this, the camshaft may or may not be where it needs to be due to variances in camshaft and/or timing gear manufacturing.  You can very easily find too much advance in a camshaft installed at the zero marks on the gears which in turn have you using a retard slot on the lower gear to place the camshaft in the optimal position.  Or the opposite where the camshaft is already too far retarded just requiring even more advance at the lower gear to compensate.

I trust some if not all of that made sense.
Other comments always welcome.

Degreeing in the camshaft – Part I – Finding TDC – Eaton Balancing
Degreeing in the camshaft – Part II – Phasing the camshaft – Eaton Balancing
Degreeing In the camshaft – Part III – It’s twelve pins between the marks for the Ford Y – Eaton Balancing

Lorena, Texas (South of Waco)

I am using a new Double Roller Timing Set for my stock rebuild. there is advance and retard settings on Cam Gear. I read somewhere that advancing the Cam a couple of degrees gives a little more low end Power. Is it worth doing this or leave it alone at stock setting?