Great pics that show what you have! It is absolutely a small block 727. I'm not at home, so I can't look up the pan rail number in my white books. It is possible that the numbers matching transmission could have failed sometime early in the cars life and got swapped out at a transmission shop...
The VIN pad is on the passenger side of the transmission bellhousing. It is a raised pad with a flat machined surface. It is probably 18" to 24" straight back from where you took the pic of the engine VIN. Good luck with the sale.
It appears to have originally been a black car, so the paint code should be TX9. Also looks like it was an air conditioned car, so there should be an H51 code on the fender tag. I know CT is a state that doesn't issue titles. Do you have paperwork so that someone could get a title? Last...
There is a factory exhaust hanger on the drivers side, but not the passenger side. That indicates it was a 318 car. The sway bar is factory installed. If it hasn't been removed, it should have one on the front that goes thru the K member and attaches to the lower control arms at about the middle...
It will either be a 318 car or a 340 car. Do a VIN search for JH23G3B218554 and JH23H3B218554 and see if you can find anything. If there are seats with it, look under the seat springs to see if you can find a build sheet. It would be a good idea to get a private investigator to run those VIN...
The engine VIN pad is on the passenger side, right above the oil pan rail and near the drain plug. If it's still up on the lift, you can find it easily. The one under the front of the drivers side head is just engine plant info, etc.
The car came out of the LA plant with a 318 2 barrel (E44), (D31) 904 (D34) light duty TORQUEFLITE and 2.76 rear gears. No amount of AI dipshittedness is going to disprove that. Just sell it for what it is.....a very nice car!
https://www.mopar1.us/6971codes.html