I usually find my missing bags of bolts by either blaming my wife for throwing them out, or by purchasing new ones. Either method will often make the lost bag show up before I have a chance to install the new ones. You can try to just go to the hardware and buy random hardware. I don't know that the lost parts gremlin is astute enough to know the difference.
BTW the flywheel-to-crank bolts have very shallow heads on them, to prevent interference with the clutch disc. I believe that 350 flywheel bolts will work. Make sure to use blue Loctite on the threads to hold them in place and to prevent oil leaks.
Carl
