I was told titanium valves not the best for street, how about titanium on intake/stainless on exhaust? Also anyone know of a good cam, also have Victor 351 intake for these SVO heads? thanks for any info.
Original Post
What happens is, both intake & exhaust stem tips chip from rocker arm impacts unless you use hardened lash caps, and the exhaust seat areas spall from heat & impact over time. The caps have a bad habit of popping out of position, instantly producing a 3/16" lash on that valve. In addition, the stems of Ti-valves are plated to prevent seizure and micro-welding to the valve guides. This plating is not very thick so used valves seen on E-Bay etc have already reached their safe end-of-life spans as far as the pro- teams are concerned. It affects new valves, too and how long the safe lifespan on the street is, is a guess. For the extra 500 rpms the lighter valves might give with an optimum cam, its IMHO not worth the risk of valve failure for the average street engine, which will likely not be torn down for inspection every 500 miles. Personally, I used Milodon 'Megaflow' stainless intake valves with a cut-down stem section in the port area, and std Milodon stainless in the exhausts on my A-3 heads (last checked in 1990). The cut-down stem theoretically increases flow & slightly cuts weight. But practically speaking, unless you have the heads professionally flow-ported (at $1000 or so each), either type of valve (Megaflow or Ti) will gain the avg steet engine little except bragging rights.