Inliners International Forums General Discussion Engines 78 chevy g-20 engine ID

The sum total of my 292 knowledge ends w/ the '72 model year, but I think you are confusing the block casting numbers on the passenger side rear [above the dipstick] with the dress numbers stamped into the distributor pad.
On my old '67 block they stamped FO626UH. Looking up the last 2 letters in the LMC catalog shows "UH" was stamped on blocks in 1967 and 1968. I'm pretty sure the rig I pulled this block from was a '67 longbed stepside in forest service green. The block that originally came in my '68 orange stepside was stamped FO627XAE. The "XAE" I've never seen explained on any chart. Leo Santucci says "the numbers stamped into the distributor pad indicate where the block was cast and its dress: (what compression ratio and accessories it had)."
As for casting numbers and date code, I have a '63 model year 292, its dress # is F III 6 PG, cast on Con 2, K 12 2 and casting # 3789404. That means it was cast on November 12 1962 on Conveyor 2.
On the '67 block [dress: FO626UH] it reads: Con 2 F 22 7, casting # 3921970. (June 22 1967). But I can't get to the '68 casting numbers tonight w/o waking up the whole neighborhood.
Hope this helps.