With knock and intermittent no oil pressure it is definatly recommended to have it torn down and inspected.  Then rebuild, replacing what is needed.  If the heads were recently overhauled that might save you some $$$.  But you still want to have them checked. 

I've had good machine work done by Dougans in Pedley (if there still around).  I don't have a good recommendation for some place that will do the complete job.

My knock turned into a rod through the oil pan; needs a good lookin' at; check the bearings, torque, etc.

You have got to remember to NOT hit the nitrous when it is already knocking 

J/K

the scoop is pretty much what caught my eye also she sure does look pretty in the water