View Full Version : Hardened Valve Seats?
I have a set of #670 heads that I am going to put on a freshly rebuilt 400. I am running stainless valves, roller rockers, and Crane valvesprings. The engine will be for street use and will be driven routinely. Should I have hardened exhaust valve seats installed?
Also, do I need to do a valve job on these heads, I have plenty of seat-to-valve contact. Thanks.
I have a set of #670 heads that I am going to put on a freshly rebuilt 400. I am running stainless valves, roller rockers, and Crane valvesprings. The engine will be for street use and will be driven routinely. Should I have hardened exhaust valve seats installed?
Also, do I need to do a valve job on these heads, I have plenty of seat-to-valve contact. Thanks.
Old Man Taylor
01-05-2000, 11:01 PM
I believe you will get a lot of mixed input on the need for hardened seats on the exhaust valves. My personal experience (with the 670 head) was that the exhaust valves recessed significantly without it. This was after several years, and quite a few thousand miles. Even with that, the engine was still running great. Unless you are really bucks down, I would do the valve job and add hardened seats. If your short block is freshly rebuilt, why not make it a complete package. It is always nicer to have it completed to the same level the first time.
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Jim
Phil69GTO
01-06-2000, 12:53 AM
79TA, I agree that it makes sense to go with hardened seats unless money is a factor. You'll get a lot of disagreement on this issue but I think its cheap insurance on a car that will be driven frequently.
Bob Dillon
01-07-2000, 01:37 AM
Go with the hardened seats now and save
worrying and/or teardown time later. Doing it
right, ONCE, is always an advantage, or so
I've heard.
Bill Boyle
01-07-2000, 06:22 AM
Leaded fuels helped prevent exhaust valve recession. The hardened seats give a much higher level of protection with today's unleaded gasoline. Consequently, I agree that your machinist should put them in. In addition, go ahead and have the 670's fully reconditioned--that's the best way to know what you have from the start. Good luck.
[This message has been edited by Todd (edited 07-18-2000).]