Cadillac ld8 engine

Check the 02 engine code on vin number. If its the same yes. You also should get the 02s pcm.U need to find out if the 99 has the same pcm as the 02. This can be done at the dealer parts department. Have them look up the pcm for a 99 then they can look up a 02 to see if there the same. Most parts have a window and are used multiable years. Gl

So by the engine code do u mean 8th diget if so they both are Y. And what if the pcm doesent match. See I planed on taking every thing from the heads down from a 99 and using every thing from heads up from an 02. What is the pros and cons and will it still work

Are u replacing the motor or doing a head job?

My Cadillac 02 deville threw a rod so I guess it's called a complete shortblock

This is possible but you will have to send the heads to a head shop and have them checked. If u dont recondition them then have them checked for cracks and warping.Y dont u just use the whole 99 motor?