Hey guys. Sorry so long. Just got an E on the post going awry. LSmith, the seats are hardened. The valves are stellite. The guides are "parent bore", which is the standard for late model stuff, gas or diesel. The casting itself is a new iron/ nickle/ carbon cast, that is actually a very fine material, much better than the 12V's, and heavier and harder than the hubs of hell, hence the lack of hardened replaceable guides (weigh a twelve valve head or similar size head, then try to lift this one). My "premature" failure has been attributed to several factors, after extensive failure analysis (didn't have time to delve into it last week). The number one cause seems to be the lack of Amsoil (or any other pure synthetic) seeping past the rather extreme valve seals. The guides run pretty dry. Cummins and other HO builders say petroleum based or blends only. NO PURE SYNTHETIC IN ISB's. I did not know this until now. The second being the fact that, yes, this pig is pumped up pretty high (check profile for the build). It has seen 32-36psi boost on every shift for over 90,000 miles, and USED to regularly hit upper 40's to mid 50's boost messing around. After the pump, timing, head deal over the last month, it now slips my 600hp Southbend at 1/2 throttle on stage one at 40psi, so the power to the ground is kinda ridiculous for the way I drive. Proper lube would have helped this, but premature failure was almost a given. I AM MY OWN WARRENTY STATION!!!!!!

Not cheap, but fun for a while... Gary KJ6Q, guides were under $100 including overnight FedEx from NV. Entire head job with extensive porting was just over $300. Much better than a $1000 ReCon... Silver Bullet, they really are good motors. Try to get this much torque out of a V motor and see what you get, then try to make it hold together. Pop an injector on a PSD or Isuzu, $320 a piece minimum plus labor. Pop a head gasket or more, and the truck is totaled unless you re-finance. I'll stick with Cummins to the end... PROSTAR, hope it went well, but the plan sounds right if it didn't!! Later guys... T