[chevy32720]

Im looking at buying a spare motor for my truck. I found a 1999 vp44 motor and i just want to make sure its identical to my current motor. Ive heard of some guys buying a 2nd gen motor and later finding out they are different. Seems like the block should be the same with slightly different components. Maybe it depends on the truck

 

[bigfish95971]

2000 should be the same as 99, but not 01 or 02, they are different. But the thing to confirm is make sure both have the Crankshaft sensor on the side of the block by the starter.
If they both have it you are good to go. The ECM may be different slightly but both will work. If you can use the one that matches the motor you use. If either motor does not have the crank sensor it is an 01 or 02.