just thought id throw this up here lost a valve keeper looked for hours no luck so got the gm part number which is 499599 which is of course obsolete.Went on SBI website and crossed to these numbers. TRW=LK129 PIONEER =PG123 FEDERAL MOGUL/SEALED POWER=VK123 these are also used on cummins L4 and L6 engines if this helps someone thats great stem diameter is .311