From planequest.com:
Operating Costs for Cessna 340
PQ Avg.
Fuel (GPH): 34.00
Fuel Costs/Gallon: 2.21
Fuel Costs/Hour: 75.41
Oil Costs per Hour: 2.06
Maintenance Cost/Hour: 70.69
Hourly Engine Reserve: 39.75
Prop T/R Reserve: 6.00
Total Variable Costs/Hour: 193.91
Average Speed (MPH): 219.20
Cost/SM: 0.88
Annual Insurance: 5,287.11
Annual Hangar/Tiedown: 5,759.61
Training: 5,192.67
Total Fixed Costs: 16,239.40
Hours/Year: 190.45
Fixed Cost/Hour: 85.28
Total Variable & Fixed Costs/Year: 53,159.91
Total Costs/Hour: 279.20
Total Cost/SM: 1.27