After you post your thread, a bar pops up along the bottom edge of your post with 'edit', 'attach', etc on it.  Use the 'attach' and see what happens.  It may take some getting used to and if I remember correctly only takes smaller pixel pics but it does work. 

I had an early 50's SAE-300 for years.  Great units.  Does yours have the six cylinder Continental engine with a magneto?  I know you can look them up with the serial number but I have to remember how to do it.  Maybe one of our regular rebuilders will come along and give you some pointers.  You should even be able to download a owners manual for it.

Have a Great Day,  Brent