I run two into the exhaust mani and always will. My superjet has a B pipe, head, and porting. I run it very hard since I have to do lots of boat chasing and I do some river riding too, and just cruising. When I'm getting to a ride spot, I'll be varying throttle position but I'm over 5500 rpm most of the time and usually varying from 6000-6900(WOT) for a couple minutes... Never complete WOT for more than 5 seconds.
When I come back from riding that hard you can only hold your hand on the sides of the block for a couple seconds without it getting very uncomfortable. Not enough to sizzle or smiting, but it is very very warm.