Will this engine be compatible with this body.
 

Hello, I have a 2000 Chevy Blazer automatic with a great motor but the truck was totaled and I am wondering if the motor will fit and work in a 1999 Chevy Blazer body?

Thank you.

as long as the engine size was the same the transmission will line up. There weren't a ton of changes in the second generation styles. I'm assuming its a 4.3 you're wanting to swap so as long as the other vehicle also had a 4.3 the motor mounts and bolt pattern to the tranny will be the same.

Yes it will! However if one is 2WD and the other is 4WD, you will need to switch the oil pan and possibly the oil pickup tube.