I thought all 79 TA auto were 403's
 

Saw a 79 TA for sale on hemmings it is an automatic, PHS shows Pontiac 400. Currently has a Chevy 383. I'm not buying, but always thought 79 TA with 400 were 4 speed only. Thanks

Fudged PHS, or bad description would be my bet.

Don't forget beside the Oldsmobird's engine code K, there were 301 auto & 4speed combo's avail too. engine code W for the 301 4bbl engine.

You could also get a 301 4-spd in 1979. But the only transmission behind a real 400 Pontiac was a 4-spd.

Looked a little harder at the ad the document showing Pontiac 400 list a different vin than the actual car for sale. Must have been used as an example in the PHS packet. Small detail that Pontiac buyer would likely catch. With original engine gone, I'd put a 400 in it.

https://www.hemmings.com/auction/197...rans-am-506240

There is an interesting '79 TA 301 automatic on BaT right now. Love the color, but you know I'm a little odd like that.

https://bringatrailer.com/listing/19...d-trans-am-14/


https://bringatrailer.com/wp-content...?fit=940%2C627

The ad is dodgy in general. 'Car was built with a 400'. Certainly not from the factory, perhaps it had one at some stage but doesn't say as much. VIN shows it as a regular 403 Auto 79 TA. Paperwork is unrelated TA. So that's 2 mistakes. Hopefully, the paperwork pic was indeed an error and they've created ad based on it, rather than the actual papers that came with it. They've listed the correct VIN in ad which confirms, along with photo and details, that it's not a 400 car.

To be clear, they made about 8000 301 automatic 1979 Trans Ams. Doesn't affect us here, but they're not really rare.

Or desirable, unless you're swapping to 455!!!