Found this config fix posted at Sim outhouse, does the trick regarding speeds, more realistic

, changes in Bold
[GeneralEngineData]
engine_type = 0
Engine.0 = 6, 0, 0
fuel_flow_scalar = .85min_throttle_limit = 0
[piston_engine]
//Lycoming O-320D
power_scalar = 1.0
cylinder_displacement = 80
compression_ratio = 8.5
number_of_cylinders = 4
max_rated_rpm = 2700
max_rated_hp = 160
fuel_metering_type = 2 //aerobatic carbcooling_type = 0
normalized_starter_torque = 0.32
turbocharged = 0
max_design_mp = 29.9
min_design_mp = 9
critical_altitude = 0
emergency_boost_type = 0
emergency_boost_mp_offset = 0
emergency_boost_gain_offset = 0
fuel_air_auto_mixture = 0
auto_ignition = 0
emergency_boost_duration = 0
max_rpm_mechanical_efficiency_scalar = 1
idle_rpm_mechanical_efficiency_scalar = 1
max_rpm_friction_scalar = 1
idle_rpm_friction_scalar = 1
Also, copy and paste this information near the end of the cfg file:
[Reference Speeds]
flaps_up_stall_speed = 50.4
full_flaps_stall_speed = 50.4
cruise_speed = 133
max_indicated_speed = 177max_mach = 0.25