total timing reading accurate with no load?

When you go up to 3000-4000 do you still have the vacuum can disconnected? Stock distributors don't really have a good limit to mechanical advance. This is why the old school method is to disassemble it and weld the advance slots smaller. Now, we have the advance limiter plate from FBO. It's a nice piece and well worth the money for the whole kit that includes the springs too. But again, the distributor will have to come out and apart. It's not a hard job and is well worth the money and trouble. You can find info about it here.

How to limit mechanical advance in a mopar distributor, tuning for street, strip or all out racing, cure that rich stinky idle, win races