I've pulled lots of 848 heads with beat out valve seats. I live in the hills & like to haul loads & just plain stand on it so's I can listen to my fentons & dual pipes. I will always have pre smog/unleaded era heads on any engine done with hardened exhaust valve seats. It always comes up in one of these posts about them being improperly installed & causing all kinds of problems. I've had 4 of 5 heads done this way in 2 or 3 different shops & never had any problems Or heard of any body else who did. unless you've got something that sets in the garage most of the time except for the yearly parade hardened valve seats need to be installed in the exhaust.
