Okay Kiddies, its been a while since the last time I put an HEI distributor back into a small block Chev, but I think it goes like this. # 1 cylinder is at the front of the motor, on the drivers side.---remove the spark plug (actually better if all the plugs are removed), and put your finger over the plug hole. Next, bump the starter untill you feel compression coming up in that cylinder, and watch the timing mark on the harmonic balancer. Don't let the timing mark go past the 12 o'clock position (straight above centerline of crankshaft) Take your big old johnson bar and turn the engine untill the timing mark is dead nuts at 12 o'clock position. (note that it is really important to feel compression coming up in that cylinder---it is possible to get the timing mark in the correct position but have your engine 180 degrees out of phase if the piston has been coming up on the exhaust stroke, not the compression stroke)
---The rotor in the HEI distributor should be turned by hand while it is still out of the engine untill it is in the position required to fire #1 sparkplug. (That position is pointing towards the front of the car, not straight ahead, but to the first plug terminal towards the drivers side of the car from dead center when the vacuum advance pot is pointing approximately towards the center of the passenger side cylinder head ) Look at where the tang is positioned on the bottom of the distributor shaft, that engages with the slot in the oil-pump drive gear----reach down into the engine thru the distributor hole with a long screwdriver and turn the distributor drive gear untill the slot in it lines up with the position that the tang on the distributor shaft is going to be in when the rotor is pointed at #1 terminal in the distributor cap. Now, if your a praying man, a little one might be in order---lower the distributor into the hole--you will feel it when the distributor gear engages with the camshaft gear, and the stupid rotor will want to turn as you drop the distributor in farther, because it is a spiral/bevel gear.---if it turns so far that it is no longer lined up with number 1 terminal, lift the distributor out and turn it back (counterclockwise) by what you think one gear tooth would be, and put it back into the engine again. This is purely a bit of "trial and error" but it must be right, or that engine aint never going to run. now, odds are really good that the tang no longer aligns with the oil pump slot, and if that is so, the distributor will not fit down all the way into the centerhead, like its supposed to. If that happens, pull the distributor back out, reach into the motor and tweak the position of the oilpump slot, and try again. When everything lines up, the distributor will fit down tight against the gasket (gee I hope you remembered to put the gasket on first).
Install the rest of the sparkplug wires, remebering that the rotor turns clockwise, and that the firing order is stamped on the centerhead . Install the distributor hold down clamp, and tighten the clamp hold down bolt untill the distributor can just be turned by hand. If equipped with one, unplug the vacuum advance and plug the hose with a pencil or something, and start the engine. If you are lucky, and the engine fires o.k., let the car run for 5 or ten minutes to get the engine warmed up, then shut it off, hook up the timing light, and set to whatever your specs call for, Then hook up the vacuum line to the vacuum advance, and that should be it. If anyone disagrees with this method, or if I have made a mistake, or if you know a better way, please let me know, and please, make sure you've got some oil in that engine and some tranny fluid in that turbo 350 before you start this exercise.