I have a 350 with HEI distributor. When my RPM's get over 2000 the motor starts missing. I have changed the cap, rotor, plugs and wires. I can't check my timing cause all my plugs had to be rotated clockwise by one post for the car to run. I figure when the distributor was installed they turned it a little. So my 2 questions are

1. What is causing the miss? at higher RPM's it goes to machanical advance so maybe the weights and springs need to be replaced? If so would it be better to get a new distributor like MSD or Mallory.

2. Can I turn the distributor back or does that even matter?

Any and all help is greatly appreciated