Vacuum Advance or Mechanical Distributor?

[fastolds]

I have been having issues with the MSD pro mechanical distributor not advancing correctly. I can't move the distributor at all from the current position or it won't start or is very hard and the headers start to glow. I am ready to switch back to a vacuum advance but should I?
The 455 is a mild built 10 to 1 with ported heads and 850 double pumper.

 

[pontiacgp]

what degree do you have the distributor set at for idle, what rpm does the advance start and what is the total advance. For street use these engines like vaccum advance

 

[fastolds]

what degree do you have the distributor set at for idle, what rpm does the advance start and what is the total advance. For street use these engines like vaccum advance

I am going to have to check again. It's been a while since I have messed with it.