Numbering schemes nowhere to be found at Chrysler...
You're going to be very disappointed in Chrysler's naming scheme - seeing as how most of the current production engines have 15-year lifespans they are just called by their displacement :? . Remember that prior to about 1992 the only overhead cam engine in the lineup was the 2.2-2.5 with and without turbos. Granted, the sales code is more useful since it differentiates which vehicle application - but no-one internal to Chrysler would know what you are talking about if you used it in conversation. So for reference, here are the current 4-valve engines at Chrysler and their names internally:
1.6L SOHC (the Mini engine, otherwise export only in Neon and PT)
1.6L HPD (High Performance Derivative, Mini Cooper S only)
2.0L SOHC (Neon only)
2.0L SOHC R/T (Neon only)
2.0L DOHC (export only since '00 in Stratus and PT)
2.4L DOHC (base engine in Minivan, PT, Stratus/Sebring, Liberty and soon to be Wrangler)
2.4L DOHC Turbo (PT, SRT, Mexican Stratus)
2.7L DOHC (Stratus R/T, base in Intrepid/Concorde)
3.5L SOHC (300M, Intrepid R/T and soon Pacifica)
And also for reference, the development history of the above:
1. 1.7L VW in L-Bodies was duplicated in the 2.2L for K-cars (same bore-centers, nearly same engine), stroked for the 2.5L making a tractor motor.
2. Needed new engine for Neon, couldn't afford new machining tools for block line - so 2.0L SOHC has same bore-centers as VW. At least the head was pretty tasty - 132 bhp in 1992.
3. The 3.5L makes it into production 2 months before 2.0L even though development started a year later. It is the second generation 4V head.
4. Mitsubishi wants a cheap DOHC 2.0L for the DSM cars. Chrysler has one coming out for the 1995 Neon R/T, and makes a front-exhaust version. The difference D4FE vs D4RE : dohc 4-cylinders front exhaust vs dohc 4-cylinders rear exhaust. This naming scheme appears in the engine description, but isn't used for tracking since it doesn't mention displacement. This is third generation 4-valve head.
5. The Stratus is too lardy for the 2.0L SOHC, so the 2.5L rods and pistons are resurrected to yield a 2.4L in 1996 (I think).
6. The large cars need to lose their truck motors, so a 4V 2.7L is developed for the Intrepid/Concorde. Nice motor, but 3,800 lbs is a lot to drag around in 1997. The fourth generation 4-valve. The 3.5L gets an aluminum block and active intake, but not really that different from before - other than the horsepower upgrade.
7. Problems with exhaust valve sealing prompts redesign of DOHC 4-cylinder head, dropping exhaust valve diameter but port is upgraded for better flow and water jackets strengthened and enlarged. Launched 2000 for PT 2.4L. Thus ends the backwards compatibility to D4FE heads, but much stiffer and less knock-sensitive. Good for upcoming Turbo.
8. BMW decides to go in halves with Chrysler for new small engine for Neons and Mini. Lauches in 2001 as fifth generation 4-valve, with boosted variant in 2002.
9. Lardy PT needs a bigger motor, so a turbo is added. Luckily for everyone who loves Neons, the upgrade everyone was looking for happened - and then a turbo on top of it. 2002 is a very good year.