Originally Posted By: sasilverbullet
Current situation - doesn't ping at all at 8 BTDC and no vacuum advance, and pings terribly with the vacuum advance connected.
And you said it pings even at WOT??? The vacuum advance should NOT be in play at WOT. Sounds like the vacuum advance is just dialing in its advance with almost no vacuum. As another poster said, some of them are adjustable with an allen wrench inserted through the vacuum nipple- give that a try. IIRC, counter-clockwise usually raises the vacuum level needed to engage the advance, but I'm not sure about yours in particular. Or you could try another distributor altogether. Or you could run without vacuum advance if you want- vacuum advance mainly boosts fuel economy at cruise and doesn't do much for ultimate performance
To really get the most out of your engine, you can throw the shop manual timing procedure out the window and tune to total advance. Somewhere you should be able to find the total mechanical advance that your 460 "likes" (with big-block wedge head Mopars, its around 36 degrees for example... Lima big-block Fords also have a typical number but I don't know what it is). Use a dial-back timing light and set the timing to the total advance with the engine revved up so that all the mechanical advance is engaged. Then let the timing at idle fall where it may, set the idle speed, and then either use or don't use vacuum advance. You can also get fancy and weld up the advance slots to reduce the total advance change from idle to full speed and play with the advance springs to change the rate at which the timing comes in. Fun stuff... and can get pretty involved since every setting affects every other setting.
