Sounds like the standard 327 crank pulleys, yes just riveted together, do you have the very small balancer on the crank...about six inches across....if you pull the engine down check the parting line on the crank, if its wide (1/2 inch or wider) its a steel crank good score, if its a narrow parting line ( like just a seam its a cast crank).. bah hum bug...
All the early SBC were press on balancers, do not use a hammer...use a puller to pull off the balancer easily, you can drill the hole and tap it easily enough and buy the bolt and heavy washer from Summit or Jegs then just use the bolt to pull it down upon reassembly...
`37 Ford Coupe, 406/350/324 posi
`64 C10, 350/350/373 posi
`68 Dodge Dart 370/904/325 sure grip
`69 Camaro RS/SS 350/350/307
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