I had a '67 SS.. I will go out on a limb and say that starting in '65, when the 396 was available, SS was synonymous with BBlock only until later years.. Maybe a small block could be had in the '70 and '71 badged SS... But, yes, I KNOW an SS could be had in a '72 with a small block... SS was just barely hanging on in '72-SS didn't mean much more than a bubble in the hood....Didn't even get boxed axle bars unless you got the 454...
     I still have the SS 454 '72 I got in '77..Stock, when I got it, it would NOT spin the skinny tires without power braking it... Booooo, 270 (net)hp at that time...
My '67 4-speed thought it was winter every day.. nail it on dry pavement and it thougth it was on ice... wheeeeee!!
  I've got books I can look it up, if we really get ta fightin' about it here....
Glad ta see others have good taste...