Timing help please

[Sawlog]

I need to make sure I am understanding this right.
I just put my motor back together. New heads, timing chain and cam.
I set my timing with vacuum advance unplugged to 8 degrees. When I plug my vacuum advance in, it adds another 16 degrees. So I'm up to 24 degrees. With the va unplugged again I Rev motor to 3500, the mechanical advance built into the distributor adds 18 degrees.
So with every thing plugged in and going at once, my total advanced tim8ng is 42 degrees. Everything that I have read says sbc like 52 degrees. Am I missing anything? I would have to set my tim8ng to 18 degrees at the get go to get that. Sounds like alot to me? But I don't know, I'm no expert at this. What do you all think?
My vacuum advance is supposed to be adjustable, but the timing light says it's not.

[geezer#99]

Does it ping?
If not bump your initial to 14.
If it still doesn't ping, try a couple more degrees.
Your adjustable vac advance doesn't control how much, just when the advance kicks in.
What's your vacuum at idle?
What's the elevation where you live?

[Sawlog]

Originally Posted by geezer#99

Does it ping?
If not bump your initial to 14.
If it still doesn't ping, try a couple more degrees.
Your adjustable vac advance doesn't control how much, just when the advance kicks in.
What's your vacuum at idle?
What's the elevation where you live?

No pinging, I don't have a vacuum gauge. Elevation 700 ft

[PGSigns]

Here is a couple of thoughts on timing. You really cant ad total mechanical advance and total vacuum advance together and get a number that is really achievable. Here is what you do. Pick a total advance that you want for wide open throttle like 36 degrees to start (it may want a bit more but its hard to tell) then pic what you need at idle and when you need the timing all in. So for this example we will pick 36 total, 14 initial and all in at 3000. So with an adjustable timing light or a timing tape do a test of just you mechanical timing and see what you have and then make adjustments with weights and springs to get you the amount of total you want and at the right time. Then take it for a run and see if you get any pinging or if it seems to want a bit more total timing. Once you are happy with that part then ad the vacuum back to the system. Vacuum pots are rated for when the start to work and how much advance they ad. I run ones adding about 12 degrees. I run mine off manifold vacuum. What this does is ad timing at cruise and other high manifold vacuum areas to improve idle quality and cruise fuel economy. It also will pull that extra timing out when you have a heavy load or you mash the gas to prevent the added timing from causing detonation. Now do another test drive with the vacuum hooked up and see how it runs. If you have a little detonation when you roll in the throttle you need a pot that requires a bit more vacuum to pull it in. This drops out the extra timing a little sooner when your manifold vacuum drops under acceleration. So you can see how the two work together but never really ad up to the two total numbers when running.
Jimmy