1. HB17BN - this is the "narrow belt" (11A metric automotive belt) balancer to suit the majority of grey motors (FE through EJ). It was redesigned by PowerBond to eliminate the central 1 1/8”-12 UNF thread cut in the centre bore to accept a puller tool, replacing it with three 3/8"-24 UNF holes on a 2 13/16” (71.44mm) PCD similar to the red/blue/black motor harmonic balancer.
2. HB1049N – identical to the balancer above, but designed for the "wide belt" (15A metric automotive belt) FX/FJ pulleys.
3. HB17AN – red motor balancer.
The two grey balancers are different centre bore to the red. No home-riveting needed on any of them - pull them off and tap them on in one piece, being wary not to butcher (or lose) the woodruff key.
Can you tell I've ben playing with supercharger pulleys lately
Cheers,
Harv