Looks like the 356A has an Oldsmobile in the back ! ! Can't tell if it's a 215 aluminum block, but if it isn't, it something like a 300 plus cubic inch iron giant. Like the ones that they used to put into '53 Studs and '41 Willys.
I LIKE this guy ! ! ! ! !
Update_I just went down cellar and check the Olds 215 that I have down there. The one in that 356A is a 215. The valve cover positioning is the give away. The heads are straight up and flat across the top. like a nail head Buick. The bigger all cast iron Olds V8 had angled heads.