Is that the head you had off me a while back?
Should rev with the porting and ti valve springs and retainers. 
Sure is dude. Got it built and 100 miles down the road 3 of the springs let go. To cut a long story short, after lots of calls to JNL and emails to techtonics and autotec in America I bought a new set of HD springs from autotec after about 2 months.
It now revs to around 8k with the new springs. Flows nicely, and I've port matched the inlet too. It gos pretty well.