The 340 is the biggest POS V8 Chrysler ever made.

The real reason it is a POS is the water pump bolt holes are drilled through, water gets in oil pan easily and the head needs studs, on ends for exhaust. The distributor is back on the wiper motor. The fuel pump holes need special insert in bolt threads so oil won't leak and copper silicone for insurance, same for water pump chain housing bolts. The alternator pivot bolt is a through hole too. The oil pump is in the pan. 383 B motor is the workhorse. 340 was a 4 bbl 318 with big heads. Big deal it fit in A body puddle jumper front end with jumpy little Upper control arms. 383 B body 1965 Satellite was a better car.
Good points. But, THE SAME DRIVE TRAIN, BUILT THE SAME WAY, THE A body will beat the bigger heavier cars. Compare a bone stock factory race hemi 65 belvedere to a bone stock 68 fastback race hemi! And even highly modified ones.