Harmonic balancer tightening (crank bolt) engine in car with 4spd manual transmission

Hi guys,
I rebuilt my engine, a 340 small block for my Dodge Dart, and thought it might be easier to tighten the harmonic balancer to spec with the engine in the car and put it in gear since I have a 4spd manual transmission. Now that the engine is in and this is one of the last to dos before firing this thing up, I am not quite sure anymore if this is a good idea, but I cannot explain why I am uncertain about it either (maybe just a question of nerves).
First, I thought it shouldn’t be a problem since the engine makes around 340 pound-feet of torque and the torque spec for the crank bolt is definitely less.

Would be great if you could share your thoughts/ experience on that.

Thx!
Chris