Keep hearing about frame twist with 440s

Is this a myth? Credible people like Steve Dulcich have told me frame twisting just doesn't happen with mild engines. (i have a lukewarm motorhome 440) Everyone keeps telling me a 440 will twist the K member and body due to weigh and power etc but the 440 isn't much heavier than a 360 and barely makes any more power than a 440.

I could understand drag engines but can anyone share their experience with me?