It's been about 15 years since I last rebuilt my 1948 u. And I'm intrigued by some of the new products are available now. I am currently running 13 in barrels with a hardened valve seats. Over the years of course I've only been able to buy steel valves, which even with lead additive in the gas the valves get beat up and lose compression. Now I've been online and found some titanium valves and some stainless steel valves for the big twin flatheads. Having 2 hardened surfaces sounds good to me. My question is has anybody run these titanium or stainless steel valves? How are they on the guides? And what kind of clearances are best for such valves. My old 1948 bike Melanie runs pretty hot sometimes because I am running a set of 4 5/8 inch Truitt and Osborne flywheels with high-performance corvair Pistons. I put a fair amount of miles on the old girl every year because it's my daily rider so anything I can do on this rebuild to keep her a bit more maintenance-free would be great.