V6 vs V8

It all comes down to head flow (remember 6 cyl needs 33% more air flow per port than an 8 cause of 2 less ports to make same power). Take the new Hemi from the flow numbers I've seen 5.7 flow about the same as a stock W2 and 6.1 as ported ones. The 5.7 hemi is basically a 318 with a 360 crank and W2 heads it wouldn't take too much duraration to build big hp numbers. We tend to under heads our engines, take a 340, X heads probably flow enough for 440 hp unported but you would need a lot of Cam and Compression even stock 318 heads probably could do 350 plus but they wouldn't be very streetable, pure race only.