Timing problem

Ok I found the timing marks. They were covered in dirt.
The engine is at true top dead center.

Can I set it to 8° advanced manually or should I start from 0° And use the timing light.

There is a Holley 600 on it now.
I set the idle by vacuum gauge and was only able to get 11"

There is a new gas tank and fuel system on it.
Plus I have two filters.
One before the fuel pump and one after it