timing/tune up problems

Bump it to 20 or 22 and see if it runs better. Only issue you need a bigger bushing! As long as it start hot, you should be ok.

If you have control over the mixture screws, you're headed the right direction. If not, it may need more initial. Look down the throats and see if it's dripping. Those holley mech pumps are known to kick some psi.

Vac will be a little choppy with that cam.

Put a med and light spring on the advance weights. That should get it in the area of 2500ish is my guess.