Since krzn already rained on your parade a little,it won't hurt so much when I tell you the 56 auto was a 2-speed cast iron Powerglide. The valve covers should have the staggered bolt holes as should the heads. There's a book out about Chevy casting numbers which would help you identify the parts you have. It's VERY difficult to say what any given part is worth! Best way is to get multiple sources like Hemmings,maybe some vette magazines,Craigslist and the ubiquitous flea bay to get an idea of what your parts are worth. Good Luck!
jus' an old guy,trying to get along.
'84 sort of daily driver,has 91 nose and tail. It's for sale,wanna buy it?
'79 project-LT1 motor-2004R xmiss-Rack&pinion-fibreglass springs.Pretty much done,still needs paint.Luv the 200-4R! 75 mph at about 2200rpm,yet she'll spin the 265's if you get in it! You could buy this one too!
Jesus is Lord!