Not the greatest source on the net but here. http://en.wikipedia.org/wiki/Chrysler_Hemi_engine#6.1

Its a 370 cubic inch engine. Manufactures will round up most of the time. Infact this is much closer than many other rounding jobs that I've heard of. Take the Ford 5.0L as an example.

"In the 1980s the 302 became more commonly known as the 5.0 Liter, although its metric displacement (4942 cc) more accurately rounds to 4.9 L.

http://en.wikipedia.org/wiki/Ford_Windsor_engine#302

It's a marketing thing to make the car sound more powerful. The humorous thing is the only difference in displacement between a Ford 5.8L and a GM 5.7L was 1 cubic inch as the Ford was a 351 and the GM was a 350. Doesn't the 5.8L sound like it would have a more significant displacement advantage this way having a tenth a displacement advantage over 1 cubic inch advantage? It's all about marketing, believe me I should know since that is my major.