If it's a clacking sound it might be worn injectors. If you have a solid lifter head then yes the valves can be adjusted, it is the exact same as a gasser in that regards (other then clearances)You say that when it runs away it goes to redline and then holds there, that leads me to believe it is a problem with the pump and not blow-by because it if was caused by blow-by it wouldn't stop at redline
A video would be awesome
Try unscrewing the residual fuel screw a little. it is on the top, back of the pump, under the LDA, and looks more like it should just adjust the idle, but it doesn't.