Using the original bolt to press the harmonic balancer back on is a really bad idea. Dont do it. When using the original bolt the stress is on only a few threads which can lead you to ruin your crankshaft threads.
Car & Truck Accessory Belts & Parts for 1974 Chevrolet Malibu for sale
Chevy Big Block 396-427 8 SFI Certified Harmonic Balancer
Other Belt Parts for 1972 Chevrolet Impala for sale
SBC Engines Harmonic Balancer Bolt Kit & Pulley Bolt Kit Compatible with Big Block Chevy 396 454 : Automotive
Other Belt Parts for 1972 Chevrolet Impala for sale
Big Block Chevy Crankshaft Pulley, 396 427 454 V-Belt - Short Water Pump, 3 Groove : Automotive
Chevy Big Block 396-427 8 SFI Certified Harmonic Balancer
2339640 CHEVY 396, 402 & 427, 1965-1972 Mark IV, 8.00” Harmonic Damper 0-Bal - PRW Performance
2339640 CHEVY 396, 402 & 427, 1965-1972 Mark IV, 8.00” Harmonic Damper 0-Bal - PRW Performance