New to toyotas need some advice on my 90 Celica motor

[Mad Mike]

I was given a 90 Celica stx its in great shape but the motor is knocking. It says STX on the trunk and under the hood it says 5sfe 2.2L motor. The thing is how do I check the motor to make sure its the 2.2L and that some one hasn't changed the hood.

Also since the motor is knocking will any of the 2.2L S5FE motor work in my celica or do I need to make sure to find a 90 celica 5SFE.

I really like this car and I want to fix it up and enjoy it. My problem is I've only owned Hondas and I can tell you just about anything you need to know about swapping a motor into a CRX but when it comes to the celica I'm lost.
heres a pic of the motor if that helps
http://i123.photobucket.com/albums/o288/cordiaturboowner/90%20Toyota%20Celica/0212111224a.jpg

thanks for any advice I can get.