Nitrous can be harder or softer on the engine depending on when it’s activated and how much is activated. If you hit the button after peak torque you can make a nitrous deal live a long time. The head and deck being flat is super important, I agree, but also the timing curve.
I'm on the Nitrous right at the start and the whole quarter mile. Car weight was 3250 lbs 170 Cid. 1.76 60 ft time and 368 ft/lbs torque at 2800 rpm. timing is fixed at 18* btdc.