Slant 6 wont start

Any insight on what happened before? You said it's been sitting because it wouldn't start, but was it fine one day and the next it would start or was it getting progressively worse? Did it sit a long time in between starts?

I agree with the basics, spark and fuel, but I'll add Spark at the right time.
Mine jumped a tooth on the dizzy sprocket and wouldn't run...actually broke the gear while I was driving and it died in traffic :)