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- Thu Feb 29, 2024 7:46 pm
- Forum: Early model JD crawler technical support
- Topic: Hardened Valve Seats
- Replies: 1
- Views: 5058
Hardened Valve Seats
I have read that when rebuilding the head on a JD 420 you should install hardened valve seats due to the unleaded gas we use today. I also understand that the 420 did not have replaceable valve seats. Would you have a machine shop machine the head to accept the hardened seats and install them? Would...