Determine engine year
I suggest the first thing you do is determine the year of the engine. The tenth digit of the 17 digit VIN indicates the year of manufacture. The identifier changed in 2001 [1997 (V), 1998(W), 1999(X), 2000(Y)------2001(1), 2002(2), 2003(3)] For the SOHC V6 the last 8 digits are stamped on the rear of the block on the driver's side as shown in the photo below by shelbygt. The first digit on the block (W in the photo) indicates the year.
I think there were some engine wiring harness changes between 1998 and 2000.
The MAF sensor and IAT sensor are integrated into a single housing with a six wire connector on the 2000. The MAF sensor and IAT sensor may have separate connectors on the 1998. Which MAF sensor do you have?
The earlier models had different configurations of O2 sensors and some had the 4R55E transmission instead of the 5R55E. Do you have the 5R55E transmission and the associated transmission wiring harness?
Since the 1998 has VIS there is wiring for the VIS vacuum solenoid but the 2000 does not have VIS. The PCM pin for VIS was switched to the fuel filler cap. If you don't have the 2000 engine wiring harness it will be easier if you purchase one. They are often available at a salvage yard or on eBay. You'll also need the 2000 fuel rails with a single fuel line connection to the fuel tank and a fuel pressure damper instead of a fuel pressure regulator. You could probably get by using the 1998 upper intake manifold with the VIS inoperative. If you want the engine to be a stock 2000 configuration you'll need to purchase a 1999, 2000, or possibly 2001 upper intake manifold that looks like the one shown below.
There is a good chance that a 1997 or 1998 engine with the original timing chain cassettes could have timing chain guide failure. I suggest that you check the left and right guide assemblies before installing the engine.
SOHC V6 Timing Chain Inspection & Repair
If the right guide assembly is broken then the engine must be pulled to replace it.
