Unleaded Heads

[Roger Coen 30751]

Go here for Supreme 130

http://home.att.net/~wildbillscorvette

[Duke Williams (22045)]

Valve train inertia

Dale's got a good point - one we often forget. One other consideration is valve train inertia. The rotators are likely heavier and would, therefore, reduce the valve float speed. This may not be an issue on hydraulic lifter engines, but if you've got a SHP or FI in your '62 this should be considered. There have been a number of threads on this issue in the past several months. The consensus of experience appears to be that unhardened seats will not be a problem unless you run the car hard (trailer towing, racing), and most of our cars don't see any kind of continuous high rev, high output service; and most of them see little mileage accumulation over time, so valve seat recession with unhardened seats may not really be much of an issue.

Duke

[Dale Pearman]

Re: Valve train inertia

Ditto & AMEN!


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[David Katterheinrich (861)]

Re: Unleaded Heads

Dale,you hurt me. No, don't have parts to sell, at least now.I do want to thank all that responded to my questiion. I should have mentioned that the heads are for a 327/250 so to a degree octane is not truly as issue, but I worried that lead might be.But, back to Dale if you are asking me about engraved parts, feel free to email me off board so I don't get in trouble. thanks Dave K.

[Dale Pearman]

Re: Unleaded Heads

Hey Dave, I'm your pal and tryin to help keep you out of trouble. Remember, I said, I've been there! And the ramifications are profound!

NO #%*&

Regards,

Varooooooooooooooooooooooooooooooooooom!


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[Patrick Hulst (16386)]

Re: Unleaded Heads

Dale,

Only my 2c worth here,

My 1971 350/270 did not, by my inspection or by my machinists', have factory-hardened seats. When rebuilt at 108,000 miles, there was obvious valve seat recession, bad enough that I went to 2.02/1.60 valves to avoid having to insert seats for ALL the valves. Otherwise, the valves would have definitely not been at stock height any longer. I do have photos of the seats (somewhere) if you need proof.

And yes, having seen that, I had hardened exhaust seats inserted as well.

Patrick Hulst

[chuck]

Re: Unleaded Heads

Here is my 2 cents worth about the hardened valve seat controversy. About five years ago I had a 1970 V-8 chev driver, it took two years of highway driving develop a valve problem (valve seat recession upon personnel inspection). The engine had 9 to 1 compression and ran great on 89 octane unleaded until the valve problem. The fix was a set of later heads with hardened valve seats, I drove it a couple of more years with no engine problems. chuck