I have been restoring this car on and off for the last 15 years. Now that i have it drivable, I need to tune it up. It is missing. I am running a 70 style of 350 and Ignition system and I think i need new plug wires. Ran a timing lite on all the wires and although i got a lite on all, some were steady strobe. Others seemed to be sporatic. I see 8mm, 7mm, stock. Also, I have seen universal fit and custom fit. Which is the way to go? I prefer stock appearance.