Aircraft- This is from the MAPA site under "Mapa log sample articles" tab. It's a pretty good read.
Level Flight Cruise Performance 1964 M20E N6966U, Full throttle, 2500 rpm, 50 degrees rich of peak, cowl flaps closed.
Altitude
OATF
MP
RAMAIR
RPM
Direction
IASKTS/MP
GPS GROUNDSPEEDKTS
10000
64
20.1
off
2500
W
128/148
156
10000
64
20.1
off
2500
S
129/149
132
10000
64
20.1
off
2500
N
128/148
157
10000
64
20.1
off
2500
E
128/148
137
Average GS/TAS 145.5 kts.
7000
65
22.7
off
2500
E
140/162
141
7000
65
23.8
on
2500
E
144/166
144
7000
65
22.7
off
2500
S
140/162
136
7000
65
23.8
on
2500
S
143/165
140
7000
65
22.7
off
2500
W
139/160
160
7000
65
23.8
on
2500
W
143/165
165
7000
65
22.7
off
2500
N
140/162
161
7000
65
23.8
on
2500
N
144/166
166
Average GS/TAS (ram air off) 149.5 ktsAverage GS/TAS (ram air on) 153.75 kts
4500
76
24.7
off
2500
W
144/166
152
4500
76
26.0
on
2500
W
146/168
153
4500
76
24.7
off
2500
S
143/164
138
4500
76
26.0
on
2500
S
144/166
140
4500
76
24.7
off
2500
E
143/164
149
4500
76
26.0
on
2500
E
146/168
151
4500
76
24.7
off
2500
N
143/164
158
4500
76
26.0
on
2500
N
144/166
162
Average GS/TAS (ram air off) 149.25 ktsAverage GS/TAS (ram air on) 151.5 kts