That #1 cylinder at TDC and #6 cylinder at TDC is only for 1980-82 engines. For the instructions, click here. Check to see if you have number 5 and number 7 spark plug wires switched, alot of times they get put on wrong. Do a cylinder balance test and see if everything is firing.
First of all you will need a 12-volt test light and about 8-12 inches of neoprene vacuum hose. The vacuum hose will conduct electricity cause it is carbon based, use an ohmmeter if you aren't sure and see if the vacuum hose you have will conduct.
Now, cut off the same # XXXXX cylinders you have in small equal lengths of the vacuum hose. 2-3 inches will do fine. The small diameter kind like to carburetors, etc will work as long as they fit over the distributor cap tower connection.
Now, mark all your spark plug wires at the cap or coil pack and remove them all. Put those short pieces of vacuum hose on the distributor cap or coil pack connections and shove the other end of the vacuum hose into the spark plug wire boot until it makes a good connection.
Now connect your 12 volt test ground clip to a ground and start the vehicle. With the engine running touch the 12 volt test light to each of the vacuum hose 1 at a time and listen for the cylinder to short out and die and drop in r.p.m. They should all be about equal. If 1 or a few don't drop or do anything than you have your dead cylinder there.
Plus if it pops back through intake and carb that usually means its too lean or the timing is off. Fire and a blown head gasket. Pops out the tailpipe and too rich. Place your hand over the carb air horn while idling and shut off some air, if it runs better than it was running too lean. Now try to shutt off the engine by completely shutting off all the air by covering the entire air horn, if it dont stall and continues to run you have a vacuum leak.
How did you adjust the valves and are the hydraulic and if so how far did you go down from zero lash?
Is the vacuum advance working. Do you have an egr?