Rear main seals

[dwg86]

I bought a 4.0 with a cracked head to build my stroker. I thought it was a 1999. When i bought a rear main seal for it...it was wrong seal. I had to get one for a 2001-2006. The rear main seal for the 1999 had tabs coming off the side of one half of the seal, the half that goes into the cap(built like the old 258 or AMC V8's). The newer seal looks like a regular 2 piece seal. So I guess my engine is a 2001-2006. Just another small difference in the engines.

[PolloLoco]

The engine Build Date Code is located on a
machined surface on the right side of the cylinder
block between the No.3 and No.4 cylinders.
The digits of the code identify:
1stDigit- The year(6=1996).
2nd&3rdDigits- Themonth(01-12).
4th&5thDigits-The enginetype/fuelsystem/
compression ratio (HX = A 2.5 liter (150 CID) 9.2:1
compression ratio engine with a multi-point fuel
injection system).
6th & 7th Digits- The day of engine build (01 - 31).
FOR EXAMPLE: Code "601HX23" identifies a
2.5 liter (150 CID) engine with a multi-point fuel
injection system, 9.2 :1 compression ratio and built on
January 23, 1996.

I don't know how a 2000+ would show up for the year code.