Shop tip to anyone rebuilding a 60s-70s engine: try not to mix pulleys, water pump, and harmonic balancer from different years. Yes they will all fit, but the pulleys may not line up.

Pontiac changed pulley design nearly every year, for many different models and applications. The water pump changed from 8 bolt to 11 bolt in 69 but there are also short snout and long snout variations. The harmonic damper changed from 3 bolt to 4 bolt in 68. My point is, try to keep the front of the engine consistent, If you're rebuilding a mid-70's 400 and want it to look like a mid 60's, take the time to match everything. Timing cover, pump, pulleys, harmonic damper, air conditioning. There are combos that will work, but many that don't.