won't start - timing?

Hey gang,

I just joined this forum; bought an 85 Caprice Classic 305 for $300 last month. It had been sitting for months, but was in great shape - owned by an old country mechanic, only 138K miles.

Obviously had some issues because of not being driven for months, so I was drying out the gas line, changed oil/filter, new air filter. Was ready to pour some Marvel Mystery Oil in when it wouldn't start.

Towed home, tried jumping, took off air cleaner, and have air being spit out of the carb.

Seems to me either stuck valve, or timing issues. My question: does the 305 have an internal timing chain or belt that could suddenly go bad, or is it likely a stuck valve?

Also, where do I go from here?

TIA,
Malcolm

Timing chain is behind the cover, which is behind the water pump.

Take off the oil fill cap (should be located in the valve cover). Have somebody turn the engine over. While it's cranking, look for the rocker arms moving. If they aren't moving, you most likely have broken teeth on the cam gear.

The chain rarely breaks, but they do stretch.

To see if you have a stuck valve, pull all the spark plugs and run a compression test. A stuck (open)valve will render a 0 compression and you may have bent a valve. If it's stuck closed, you may have bent a pushrod.

If you don't have a compression tester, pull the plugs and put your finger over the holes while cranking and you should feel air pressure.