Replacing the old overworked exhaust and inlet valves when rebuilding the engine is a sensible precaution, the old valves become brittle and can break off around the valve head area, allowing what is left to drop onto the top of the piston causing untold and very expensive damage!
Renewing all the various valve related parts at the same time is standard practice, springs, guides, stem seals, cotters etc. Other related parts you will probably wish to add to the same shopping cart:
4C81215310
1RC1211100
1RC1211101
1RC1212100
1RC1211600
1RC1211300
1RC1211400
3D71211700
4TE1211900
2C01113311
1RC1116900
We supply all the gaskets and seals you will require; order them at the same time and save money on shipping costs with a multiple order. Why not use the same sealant as the engine building professionals? 08C70K0234M - complete the job like a pro!