Dazed and Confused
Join Date: May 2012
Location: Upstate New York
Re: Cleveland 351 heads, Changing to Unleaded?
Good question, so I went looking for answers, some actually say that you can't tell if they're done right. However, some also claim that you might be able to see a seam on the edge of the seat or by looking down the bowl to the valve port. A hardened seat has to be pressed into the head and the metal will be different.
If the heads show sign of having been worked on (lead seal on the ports remade), odds are the seats are hardened. Also, if you can get a stamping that will indicate a year, that may also tell you.
Ever notice that there's so many high performance parts available for GM products?
Did you ever think that maybe they NEED them?