To many this will seem like a fairly basic question but I could use some help. Back in October I needed to remove the distributor in my 68 GT 390 to have it looked at and worked on. I was told to make a mark on the body of the distributor case and the block to have that as a reference point and also after removing the cap the location of the rotor in relation to the case. Made both those marks. Also told to look at the rotor as I was lifting out the distributor as it would turn slightly in a direction due to the gears un-meshing between distributor shaft and cam. That was a slight twist counterclockwise. Do not rotate the motor after distributor is out.
So the refreshed distributor comes back from Indiana with the newly restored and installed dual vacuum advance unit. Since my car is a Thermactor equipped and C6 auto i had the correct advance rebuilt to replace the aftermarket single vacuum advance unit. I try reinstalling the distributor lining up all my marks I made but its a little stubborn. Will only mesh in one location at it appears slightly off. But it wont go in any other way so I figure its a match. Try starting the car but it appears i was off maybe a tooth. Currently I am unable to start the car because I cant swing the distributor in the direction i need to go because my nicely restored vacuum advance is hitting the upper water pump hose from the block to the pump. So now that ive cranked the motor I need to reinstall the distributor based on TDC and #1. So here is the question.
I will crank the engine over close to TDC and then turn by hand. But do I want to actually turn it to TDC mark on the balancer or to ^ degrees before TDC? The shop manual calls for 6 degrees BTDC as base timing. Whether I use 0 or 6 degrees on the balancer the more critical question is the distributor shaft has a hexigon cam at the top of it below the rotor. That mean we have 8 points and 8 flats. The points of the cam rub on the the plastic block of the actual points causing them to open and close. It would be my guess that as the points open, meaning the cam point pushes on the points block, that's the moment that a spark is sent to the terminal on the underside of the distributor cap. So do i want to get this accurate installing the distributor? Meaning balancer at 6 degree BTDC and points open for cylinder 1? i really need to have some more swing in the distributor between the water pump and the fuel line. The vacuum big dual diaphram advance will contact both. Sorry for the long dissertation. i may also need to move the oil pump shaft slightly. Ive been told thats a 1/4" deep socket. Can it be turned either way or only one direction? With ratchet or with finger pressure?