I'm swapping a C6 to a NP435. THe engine is a 79 400. The flywheel and clutch kit I bought didnt include the pressure plate bolts. I did a search on here and read that it takes a special bolt but nobody explained why a grade 8 wont work. What makes the dealer only bolts so special?

If a grade 8 wont work, anyone know the correct part number I need to ask for at the local dealership? THanks, Dave.