A "CE" short block for a Z/28 would have come from Flint, and the date code on the block you mention pegs it as a Tonawanda block; sounds like a "CE" block intended for another application that's had 302 innards installed in it somewhere along the line. The 492 heads have 2.02" valves, but they're service replacements - never had a production application. Should run just fine, but neither the block nor the heads are "correct".