I have no experience with the early 6 cylinder engines, but the front and rear surfaces of the oil pan in the 4 cylinder engines are difficult to seal.

One of the things I encountered when rebuilding a 1928 engine in 2017 was the issue of installing the oil seals so they would not leak. I documented that journey on the old website (vccachat.org) and here is a link to the post where I made and installed the gaskets for the oil pan: Making oil pan gaskets for a '28 4 banger

Hope this helps. Cheers, Dean

There are tricks. I copied this from the 46 section of the old forum by Chevy Gene ;

When replacing the oil pan gasket the side gaskets must be stuck up onto the block first and then the end corks inserted into the main bearing caps. Pre-curl the end corks before installing. Saves a lot of swearing. I uses 4 little studs , insert them into the block, to guide the pan straight up into place. This helps to prevent the gaskets from slipping.

You can pre curl by wrapping around a soda can with rubber bands overnight. I also use a little grease to hold the side gaskets on the block while putting it together. Also a little sealant where the side and end gaskets meet. 

Try searching the old forum lots of ideas on this subject.

Good luck

Dave

I put all gaskets on the pan.  I like your input and will drop the pan and start over.

Wetting the cork end gaskets before wrapping them around the soda or beer can and letting them dry overnight is critical to forming the arched shape.