It's also possible the new L67 shortblock is from a Bonneville SSEi, Park Avenue Ultra, or even an Olds 88 LSS or L67 Riviera, any of which would require some changes to bracketry and such. Ask and see just what the donor make/model/year/trimline is.
The only relatively easy way I can imagine to visually positively ID a shortblock as having L36 or L67 internals--after installation in the car anyway--is to pull the oil pan and inspect the connecting rods from underneath. The rods on L36 vs L67 are different, in that L67 are shorter and thicker. I do not have side-by-side photos, but I'll bet someone else here does.
Almost forgot, an L36 (n/a) bottom end with a blower slapped on it will chip a piston fast if not modded/tuned for it, because the n/a bottom end has higher compression than the s/c bottom end (due to differences in the piston dish). An L36 bottom end is not a suitable direct stock replacement for an L67 bottom end (or vice-versa).
