70 Chrysler 906 head questions

[71BBGTX]

Hey all,

Set of 440 heads off of 70 New Yorker. What should be done to make these safe and durable for unleaded gas? Is just hardened exaust seats acceptable for the "long run" or should I replace valves, guides, and/or springs? Motor has approx. 130K on it. What do I look for to determine valve stem wear and need of new valve guides? Thanks for any tips/advice!


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MOPAR or NoCar!!!

[Chargerchuck]

It's smart to get hardened seats. Unless the valves are damaged I think you could get by with just grinding them. Depending on the cam you may need to replace the springs. At least have them checked. Same with the guides. It's been a while since I've had headwork done but if the guides are worn, replace them, don't get them knurled. I would also get them checked to make sure they aren't warped.

[DragRacinAMC]

Chances are, the guides will be worn. Like Chargerchuck said, don't waste time with knurling them. Have bronze liners installed.They wear better & last MUCH longer that stock guides. When you get new seats & guides, you have to have a valve job done anyway, so go all the way and mill 'em. That way, there will be no dought in your mind. Hope this helps.

[fast68plymouth]

if the heads have 130k on them, then its unlikely that the valve stems wont be worn beyond the service limit, but youll know that when you get them apart and mic them. also, if this is a motor thats likely to see alot of use, or high performance use, then i would change the valves as a matter of course. they have had 30 years of contaminants working on them, and have likely lost some of there structural integrity(in laymens terms, rust and pitting).
you should definately go with the hardened seats, bronze guides, and have them resurfaced.

[amoparguy]

Hardened exhaust seats are a must for unleaded fuel. Your machinist will tell you what needs replacing but with 130k on them, you'll probably need to replace the guides. Springs fatigue over time. Unless you are trying to get by cheaply, I'd go with new valve springs too. You are better off doing it right the first time than having to do it over.

[This message has been edited by amoparguy (edited January 14, 2001).]