Ok, my 67 has a 289 with an edelbrock 600, headers, a petronix ignition and an msd 6a box. The firing order is 1-3-7-2-6-5-4-8, which I understand to be consistent with a 351, so the cam is not original. I had a shop fix the freeze plugs in it and when it came back the rotor was pointed to number 6 cylinder at TDC. I did the trick of sticking my thumb in the cylinder hole while rotating the harmonic balancer to verify that I was on the compression stroke when it hit TDC according to the balancer. I then used a piston stop to verify that the timing mark for TDC on my balancer was accurate, which it was. I restabbed the distributor so that the rotor was pointed at the number one cylinder hole on the distributer at 10 degrees before TDC. New plugs gapped at .035. She started up with some coaxing but ran rough with below 15 mercury on the vacuum gauge. Will barely stay idling and seems to be missing. I have adjusted the timing multiple times with rpm gauge and vacuum gauge adjusting until the vacuum and rpm readings stop going up and backing off slightly. I then drive it and retard the timing until I stop hearing any pinging and retard the timing another couple of degrees. Every time I do this I get to a timing of about 22 or 23 degrees btdc, and the vacuum gauge has a reading of 18, which I believe is right, but the 22 or 23 degrees BTDC makes no sense to me. She seems to run really well at this timing setting, but I am worried about how advanced it is and don't want to damage the engine. I take it out for test drives and it does not ping as best I can tell. The jets on the edelbrok are at about 1.5 turns out. I have checked the vacuum lines on the carbeurator and the vacuum advance is hooked up to the passenger side line, PVC line is hooked up to the middle and the full vacuum line is plugged as it should be. Anybody have any thoughts on this one? I would love to be confident that the timing is set correctly or figure out a way to fix it such that 10 btdc works which I know is slightly advance from the 6 btdc that is in the shop manual for a 2 barrel. Thanks for any advice you can give.