If you are referring the ones use on the 08P and 09P then MTD PN 793P00165A is a likely candidate. It also fits the MTD 1T65, 5T65670-JUB, 8X65, 5X70. 6X70,1P51,270-XU, 775-WU, ETC. So basically they are use on the MTD 140cc - 243cc engines.
The spring comes separate so it must be ordered too. PN 732P05251.