A Magnum based stroker: 6.7L or 408?

I am not one to adapt to modern stuff quickly and the Liter sizes are one of those things.
If an engine was called by a metric number from the start, I'd be more likely to keep calling it that. a 5.7 Hemi will remain a 5.7 Hemi but to muddy the waters a little, even Ma Mopar called the 6.4 a 392 for a few years.
The 5.9 V8 was a 360 from the start so to me, I only call them a 5.9 when they are in stock form.
When they are rebuilt with shaft mounted heads, screw that metric crap...it is a 360 in my opinion!
My 13 year old nephew has been coming around to work on cars and we are going to fix up the 72 Duster for him. When he asks of the engine sizes of the cars out back, i have to convert the cubic inches to liters to give him perspective....the 440 is 7.2 liters. The 440/495 is over 8 liters! His eyes get big when he hears of how big these engines are compared to new cars.