My '79 bronco with a crate 351m with 3000 miles recently quit starting. I moved it one day (it ran great) and now it won't start. It backfires through carb pretty bad. I was told to check timing, upon that I noticed distributer gear wasn't turning with motor cranking. I pulled distrubuter and the pin in the gear was sheared off, so I put an old distrubetor in and it did the same thing. I pulled timing cover off and the timing chain has major play in it, so I ordered a new timing chain set. Is there anything else I should look for that I would cause a problem like this that I need to look at while this is apart?