Hello All, first post!!! I have an 87 Trans Am with the 305 and 5 speed. I have an opportunity to get a 4th gen 5.3 out of a Yukon, it comes block, piston, crank, cam, and LS7 lifters, tho I might bore and stroke the engine. will it line up with the stock motor mounts? is it considered a LS engine? Thank you,

 

The entire gen III and IV are generally considered LSx engines. Not to be confused with LSX, as that is not a production engine.

You should read the LS and LT sub forum sticky before asking more questions, this has been covered many times already. You will need mount adapters to put the engine in the car.