66 GTO That doesn't make sense???

I came across this one on EBAY....its a 66 and the guy selling it states that its all original....including the 400YS engine thats in it.....now what has me confused is that everything I have seen or read the 400 wasnt introduced into the GTO until 1967....is it me or is this guy just blowing smoke and trying to pull one over on the poor high bidder??? This is the item # of the auction if yall want to see for yourself.... Item number: 2458614809

The 400 wasn't available in the GTO until 1967.

Thank you!!!! Thats what I thought!!!!

I worked at Pontiac Motors during this time period and there was no 400 motor until 1967. The old Pontiac plant has a few GTO's stored in the basement with 421 tri-power on them.