There is a cam setting tool from Volvo but I think you could set the cam using the journals alone, but check into that. I used the tool. I would set the cam and tighten, then measure all clearances. Then I would remove the cam and replace all the shims with the correctly sized ones and replace the cam, oiling the journals well. Then recheck all clearances. Do not be tempted to run the car without checking valve clearances. Permatex the front journal cap ends with the proper stuff, hardening(?). Check all torques and tightening order with Bentley or Volvo manual.

If the T-belt has 20K or less, I would reuse it.