But Jim is wrong, it will run if the cam is a tooth off. Through inattention and lack of experience I managed to swap cams on an engine way back, got the timing out by a tooth and it ran quite well, other than a general lack of power. I've seen a few other examples of this since.
The procedure for checking cam timing is quite a bit different. Verify TDC and correct alignment of the timing marks on your engine first before worrying about this.
Live and learn. I've only seen terrible running engines with the timing gears mis-aligned.
