While we're on the subject of valve seat material,it used to be that valve jobs were common on many engines after maybe 60,000 miles back when.Now,engines maintain proper compression with 200K+ miles on them.Is it the seat material?
The build quality of US engines in the 70's was poor at best.I personally remember the massive cam failures in GM V-8's,mostly Chevy.Head coolant leaks too,the coolant got into the oil,spun bearings.The car makers had the technology to prevent these problems,but they did nothing until the imports made a serious dent in sales.
Interesting,the inline 6's of that period didn't seem to have valvetrain issues,probably cause they were so gutless,lol.
It's no secret that heavy duty engines often had the seats hardened or replaceable seats made of more durable material.
Anyways,build your engine the way ya want.I will still have the inserts put in primarily to get the valve heads where they belong and the stems at the correct height.
