For a longer flight, I usually do M.74-.75 to optimize Low Fuel burn but in general, I typically do M.76-M.77 (clarification)
The normal cruise speed for the 737 is 0.78 Mach :)
This was only used on early 737 models, such as the 737-100,-200 and -300.
Usually the 737-700 will use 0.78, the 737-800 and 900 use 0.79. 👍
Not sure about other models, but the 738 uses M0.77-0.79, 90% of the time it would be M0.78. M0.81 is MMO.
I usually cruise at M0.76 to M0.77
That’s usually at FL360 to FL400
Here’s some aircraft data you can check out.
MACH 0.77 to MACH 0.82
You’re going to be higher than the MMO at .82