I'm not exactly sure of what you're doin', but I don't think you can time a 300? They don't have
a timing chain, just a timing gear, well atleast mine does. Are you trying to adjust something through the distrubutor?
Sorry, I'm not much of a help!
1982 F100 Flareside
300" T18 4speed
Blue & Silver
What yr is the truck engine ? On the EEC IV system , you will have to remove the SPOUT connector ....Its two wires that are next to the Distributor Cap and the wires have a square , Usually Grey , connector that you remove to check /adjust the timing . Place the inductive pickup from your timing light on the No.1 spark plug wire , the timing mark is NOT the big indentations on the crank pulley , the timing mark is a smaller mark that is best seen if you find it with the engine off and dab some paint across the mark . Unless the distributor was moved or some other work was some to the timing gears on this engine , its unlikely the engine will be out of time since , as mentioned in the previous post , it uses gears ...one on the crank and one on the cam . The gears dont allow the same wear and slack as a timing chain does .
If yours is the '82 F100 mentinoned in your signature, then you should be able to adjust the timing. All the manuals say that distributor should not be moved, but I know I had to get my 300 I6 timing changed in California to meet the emissions test. I've never done it on the six, but I would guess it means to have to pull the distributor and actually moving it one cog to change the timing. I don't think that you can loosen the 300 and turn the distributor like you can on the V8s. Just be careful and continuously check the timing whenever you make an adjustment. The timing should be checked with the vacuum hose removed from the advance pot and the vacuum hose should be plugged.