Ignition timing

[chvtrkman]

Sorry if this topic has been discussed to death. I did a search but turned up nothing specific to my problem. Here goes:

My 292 has no power above 1500 rpm. I went to check timing yesterday, I put the timing light on it....can't find a mark lining up anywhere on the timing tab on engine block.My question is, would my truck even run if the distributor were to have gotten off a tooth? I didn't pull the dizzy, but a friend who worked on it for me in my absence may have.Any clues?

BTW: the truck is a tiny bit hard to start when cold, but once it idles a minute or two it starts easily, idles ok, and revs ok. just when I drive it, it cuts out after 1500 rpm, and has little to no power to climb a grade. I haven't checked for a vacuum leak yet as I want to make sure timing is correct first.Any help is appreciated.