"hole in the cover" needs more clarification. Which hole or are you referring to - the vent tube hole or the pcv hole?
The glove box decal sez the truck was ordered with a 292 so I suspect the 250 came later as you suggest. There is no evidence of a brake booster, so the offset air cleaner is still a mystery although the GMheritage pages show the 192 and 230 to have the offset cleaner in the pix.
I like the look and intend to keep it, but all good info to know.
HB
