In theory, that value should be about the same for both the G37 and Z, so assuming the value they entered was correct for the G, you should be in the ball park.
I'm just wondering where the public can find these values listed.
It should be public domain info but I can only find references to it and no actual tables with data
Anyway, notwithstanding the degree to which any given dyno reports "true" values, I find that you get less consistent results between load holding dynos vs. inertia dynos because different values may be entered between shops.
I say, find a place with a dynojet. Your numbers will be easier to compare and contrast as the key value of relevance (the weight of the drum the wheels accelerate) is fixed from unit to unit, and thus results are far more consistent (i.e., reliable). Then you just have to note SAE values vs uncorrected and or STD, as well as the gear you are in (4th is fine, although derived torque values tend to be a bit lower relative to 5th).
In other words, the values different individuals get from shop to shop on Mustang dynos are harder to compare than the values folks get from dynojets, and at the end of the day, THAT is how to most clearly conclude anything about how your VQ37 compares to others.
If you go, ask for the drf (actual data file) -- if you email it to me I can make comparison graphs of your output vs several others.