I was thinking of changing my current coil (yellow top) and current single vacuum advance dist. I'm using a female type dist cap. I'm thinking this might help in performance. I changed the plugs and wires this weekend still skips a little under load. I have a new 670 Holly im sure it needs a little more adjusting to take care of that. I was hoping i could get some ideas on what other people are using that works good. I have a 1969 Mach 1 390. Thanks for all the input.