is the engine not running at the moment? Just trying to establish where we are in the process. Also, what carb are you running, what cam, are you running headers, are there any other modifications to the engine, etc.? All this has a direct impact on setting timing.
If it isnt running, you need to
- get the engine set to Top Dead Center (TDC) by rotating the engine (by hand or bumping the starter) so that the line on the harmonic balancer is lined up with the mark/plate on the timing cover
- make sure the rotor in the distributor is underneath/pointed at the #1 spark plug terminal
- ensure all of the wires are correct as per the firing sequence (18436572)
This should allow you to get the engine running. You might have to advance/retard the timing a little to get it going (you want the distributor clamp snug but not super tight, ideally you want to be able to move the distributor by hand but frequently you have to have it tighter so it won't move when running, thus requiring a wrench).
You will need to disconnect and plug the vacuum advance.
You are going to be dealing with 2 timing settings; base (initial) and total. While the initial is a published number, the reality is every engine is different and depending on what has been done to it, what is on it, the initial number may range from 0 deg to perhaps 15 deg or more. My 440 runs 15 deg initial. Basically, you are trying to find an initial that allows the engine to start (hot and cold) well and idle.
The second timing issue is total; this is typically around 36-38 deg (again depending on what your engine wants/needs). This is accomplished by raising the RPM once the engine is warm/hot to around 2000 - 2200 RPM and adjusting the distributor or modifying the distributor (weights, springs, etc).
There are many here who far more adept at this than I am and can go into extensive detail about how to achieve the best timing possible. You do need to understand that timing is but one component in the overall operation of the engine, everything is reliant on everything else to work as best as possible. What I mean is that timing is only one issue in many that have a direct effect on the efficiency and drivability of the vehicle. Everything must play well together and this is where the real magic is. In other words, you get set the timing and get it to run, but if there are issues with the induction, exhaust, cam, etc. it is going to be frustrating (which is what hot rodding is all about)