You can use the one piece seal from the 88 and newer 350's. The mains would need to be line bored and the block machined for it.

http://www.enginebuildermag.com/Article/1766/Old_Iron_Sealing_Stovebolt_Chevy_Engines.aspx


1954 3600 Chevy Truck
"The Fake Truck"
In the Stovebolt Gallery
More pix on Photobucket