Rachel has 1500 - 135 - 141 envelopes = <<1500-135-141=1224>>1224 envelopes remaining to stuff.
Rachel has 8 hours - 2 hours = <<8-2=6>>6 hours left to finish the task.
Rachel needs to stuff 1224 envelopes / 6 hours = <<1224/6=204>>204 envelopes per hour.
#### 204