If its an early block the main and head studs will fail long before you would need filler.the early blocks had head studs that were only .900 thread engagement into the deck.the main studs were only 7/16 with short engagement as well and would pull out under high power use.best thing for early blocks is street use,look for a Brodix or Dart if your going to put out some power and they done need to be filled.Bill