I think the 340 was a “6-pack”
Both the small block 340 and big block 440 were available with three 2-bbl carburetors. Dodge called them "Six Pack" and Plymouth called them "6 Barrel."
The small block version was only available in 1970 in the Dodge Challenger T/A and the Plymouth 'Cuda AAR.
The big block version was originally released in the 1969 Dodge Super Bee and Plymouth Road Runner. In 1970 and 1971 it was available in many more models including the Cuda and Challenger, and a few other B-bodies. Not available in 1972 year models.