I think I understand.
The 348 is W74, an HO engine. You could then option it with T42/611 to make it a RA car.

The factory docs and order form are clear: T42 is an add-on, very much like the cowl hood was on a Camaro.

Invoice RPO's are clear, I don't see much interpretation, even if the verbage changes.

Some engine components could be changed due to T42 if they were not part of the engine as shipped (carb and fan were not). So it is possible.

This is where a database comes in handy. The same type of issue on some the 396 Camaros. Docs show two different carbs used, but turns out only one shows up on cars.



Now the question that will never be answered is: why was the invoice description of 348 changed in Nov. It would be interesting to see if the verbage on window sticker also changed, since that appears to pull from a different database.

Note that the price of 348 changed throughout the year:
In Nov, it was $253 invoice $.
That export car was $278.
The June car was $302.
An April car was $314.

And here's the kicker. I have a PHS for a Nov built LOS car (exactly the same time at the Nov 'RA' cars) that wasn't invoiced until the end of March. 348 was $306 on that car. And it's 400 H/O on the invoice.

Do either of you have the VIN's for the invoices posted at the beginning of this thread?