I've seen A LOT of posts about making HP with a 318-So why is it so ???

Many reasons people tend to build anything that is considered less than the ultimate.
Why? The challenge. Mopar people have always been less than mainstream. Why LA 318, even poly 318 (A motors), why a 383 and not a 440? Whyput any$in a slant? Challenge.
Money. If $$ was not a factor, 99% of us wold be running a 426 hemi maybe? In a 71 Cuda maybe?
Not everyone has to be the biggest, the baddest, the most complicated, the most expensive... to enjoy this hobby.

Don't convolute this thread with anything other than the 318 please. To wit--If it is all about $$$$ The 360 wins with its 4" bore making good pistons far cheaper than a 318. So why the 318 if its all about $$$? Yes I am biased, I pretty much view 318's as something I wouldn't sink a nickle into and I often push my customers into finding a 360 as it is BETTER and CHEAPER. J.Rob