What would be a good limit for a built D series?

Anyone have a Dyno graph of a D series motor reving past 8000?
I am wondering if the power will fall off because of the D series R/S ratio.

If The motor will continuily make power past 7000 I will end up building my spare ZC head for RPMS. If not, I will just leave the head stock and use the stock rev limit.

 

My engine builder told me he wanted to spin this thing upwards of 8500rpm to achive 400whp which would require ALOT of balacing of the crack especially.. I dunno if I'm gona stick with him though.