Clicking In The Engine

Yes thanks for explaining the NEED to adjust valves on solid-lifter engines. Sometimes it's easy to forget that not everyone automatically knows why things like that are required.

Now the OP knows that with solid lifters there always needs to be some clearance in the valvetrain and his responsibility is to ensure it has the correct amount.

To add:

Too MUCH clearance won't really hurt the engine, but noise goes up and performance goes down slightly since the valves aren't opening as far as they should.

Too LITTLE valve clearance can be bad, bad news if allowed to remain that way for a while. Valves, especially the exhaust valves, are subjected to intense heat. They shed part of that heat each time they close and rest flat on the valve seat.

When the valves are too "tight", not only do you get a slight miss because part of the combustion pressure is escaping past the valve(s), but the scorching hot gases can start to wear away at the valve itself and before long you end up with a chunk out of the valve face.

When that happens, you have a "burned valve". Compression in that cylinder goes to 0 because the valve is no longer capable of sealing. The head has to come off and a new valve installed. Plus normally a full valve job, so...

If you own a Slant six before they went to the hydraulic lifters, keep the valves adjusted regularly.