The Rocket uses a chrome steel cover that slips tightly over the oil filter. Friction fit. Should stay in place when forced on.
If you lost oil pressure, I'm pretty sure your main and probably rod bearings are seized on the crank. If they spun in the main bore, the crankcase will be toasted. We had someone a year ago or so seize an engine when he lost an oil pump. Went with a Pinwall engine if I remember correctly and it worked well for him.
