According to the Nova Resource site...these are the stats:
TH400 in Novas...
**note these totals represent all engines available with the TH400
1968...98 (50 of these were in the Gibb Cars w/L78..the other were L34 applications)
1969..1411 (L78 and L34)
1970..1238 (L78, L34 and LT1 in the Deuce)
The L78/LT1 applications used the high shift point/HD versions of the TH400.
So, regarding rarity...there were a lot less automatic cars produced than the 4 speeds...does that make them "rare"...I guess so, though most folks like to row the gears [img]<<GRAEMLIN_URL>>/
[/img] From a performance stand point they are very durable and almost impossible to break...just put it in "D" and let it go [img]<<GRAEMLIN_URL>>/burnout.gif[/img]
***my sense is the TH400 might be more common in the L34 applications as a percentage of the total cars produced...but, this is just a guess...seems like I've seen more L34 auto cars than 4 speeds [img]<<GRAEMLIN_URL>>/hmmm.gif[/img]
Fisher Body "build sheets" commonly found in the back seats of Novas will not list the selling dealer...you will need other documemtation or owner history to answer that question. Sometimes there are clues in the car...old receipts, oil change stickers,dealership "identity" items, etc. that might help you.
Hope this helps..wilma