390 vs 408

Wow! This turned out a bit hotter than i thought! Calm down people!
I have gotten a lot of help from this thread though! Thanks for that!
More opinions will absolutely not hurt, and hey, I think the 318 that's in the car is pretty fast :cheers: but I have an undying urge to build crazy engines and go fast :snakeman:. At this point, having read the whole thread I'm actually leaning towards a 390.

But hey! Anyone else?