I just wanted to update this thread.
Well, the machine shop/ engine builder said the problem with repairing my old head was that he couldn't align-bore it, as he's really only equipped to work on V-8s.
So i went ahead and bought a 9500 mile used head and cams to replace mine.(Got a sweet deal too!) I checked it and it has nearly .003 thousandths worth of flop at the ends of the cams. Far better than what i had, but a clear indicator that these heads are prone to wear out quickly.
I re-ringed the 904, got it running and have put 900 miles on in 2 weeks. She runs great, has acceptable noise levels, and no oil leaks. I'm happy with it for now, but sure miss the lope and extra torque of my stage 1 cams and ported/polished head!
I suspect there are a lot more very-worn heads running around on higher mileage bikes. If you plan to keep your bike for a long time, i'd advise keeping your eyes peeled for a spare head...
