I think I have my answer here: (quoted from: http://www.ontario.ca/laws/regulation/980361#BK5)
(2) A hot rod that receives a motor replacement on or after January 1, 1999, shall receive a motor designed to meet emission standards at least as stringent as those achieved by the original motor with all its original emission control equipment attached and functioning, and the replacement motor shall have the original catalytic converter and all the original emission control equipment, or equivalent replacements, included or usually included with the replacement motor by the manufacturer of the motor. O. Reg. 361/98, s. 4 (2); O. Reg. 86/99, s. 3.
