The 340 is the biggest POS V8 Chrysler ever made.

There were lots of good motors back in the day. Chrysler did not make any POS engines back in the day. The POS, to get back to the OP intent, were: SBC except the 327 and 283 and some HP 350; BBC except the 427; Vega 4 cyl; Plymouth Cricket 4 cyl; Pinto with the Ford 4 Cyl with the deleted valve train oiling. Definitely not a 340. I was working on them all, back in the day. I am talking running on the street, daily driven, not some hyped up drag racer with no Chevrolet parts in them. You can make anything run if you throw enough money at it. It also doesn't hurt when sanctioning bodies penalize anyone faster than you to boot.