Ok, this is what I found out in case anyone is interested.
There are two main codes on a block that can help identify a 4.2L engine
1st. ENGINE DAY BUILD CODE. This is located on the passenger side of the block just below and between #3 and #2 spark plugs holes. It's a flat plate and has this format:The Engine Day Build Code consists of six characters:
- Year built code 2 & 3. Number of the month 4. Engine size/type code 5 & 6. Day built
Mine is 012C05
Which comes out to:
0=1980 or 1990 12=Dec C=2v carb 05=day of the month builtSee this site for more info:
Mine reads: EF3235444
When I looked for this number on remanufactured engine sites I see that this block serial number started in 1981 through 1990.
Therefore the best determination I can make is this engine is a 1990 made engine.
Hope this helps someone.
Bill