I use Scat. I sell Scat. They are one of the best lightweight cranks for the money. I think they are 1500.00.
I have one that's balanced to Scat I beams and Ross flattop pistons, don't know if you'd be interested. I'm not trying to sell you on that though...
I just feel that the extra stroke over the 318 crank is worth it. You will need a solid roller cam and lifters to run that rpm for sure. Once you get a good combo to spin that high and make power up there, you'll have alot more than 400HP. I would figure closer to 550HP and maybe more.
So you could put W2's on the 318 to keep HP down...I guess?