distributor timeing?

Well if you got it that close without a light then you might only be half a degree off, I would consider that very good. As far as damage is conserned, I would seriously doubt you could do anything more than nil. For setting the timing with a light, Connect the power leads with red to red and black to black and the last lead should clamp around the No. 1 plug wire, anywhere along its length between cap and plug. Then just do what you did before. It's pretty simple

You can set timing with a 12 volt trouble light if its got alligator clips. Remove the distributor cap to prevent the engine kicking over and connect the light between the positive connection to the condenser which is probably on the side of the dist. and a good ground. Turn the engine over till the timing mark lines up (maybe loosen a couple of spark plugs to make this easier) and switch on the ignition.

The points short out the light when closed so the light will be dim or out. Adjust the distributor until the trouble light just goes from dim or out to bright. Since the system throws a spark when the points just open, this is the point when the No 1 cylinder should fire. I used this system for years on a couple of different cars and when checked with workshop instruments the timing was always spot on.

If you take the truck for a spin when it is hot and you give it a lot of gas and you don't hear the motor pinging then you are OK!!

So long as the engine is not idling strangely or chugging you should be fine. If you notice any of those things then you may need to recheck it.

is it pinging? if not its probably all right :)