The 33 in 3314 and the 40 in 4018 is just a number. It is easier to resticker 2 different saws and have a bigger line-up than it is to retool for several different pistons and jugs. it saves them money in production and warehousing parts to make a one size fits all engine and do a color change on the injection mold machines for the cases.
They have a myriad of color schemes, stickers and bars/chains for basically 2 saws. One is anti-vibe the other isn't. If you check the ID tag on the back of the saw there is a line that says Displacement: 42cc. This the same from the 3314 to the 4218. The line-up directly preceeding these saws were basically the same way. They had basically (2) 36cc and (2) 42cc engines with minor differences depending on year, AV or non-AV . One set had chrome bore the other had a chrome piston.
The main differences, besides color and anti-vibe, is the bar length and the chain. Most will have Oregon 91VJ chain, the rest will have 91VG chain. From what I've seen, the run-of-the-mill Pxxxx series gets 91VJ the PPxxxx series seem to get the 91VG.
The smaller framed PP295/PP4620 is in a different line-up.
