He won't hurt the bottom end it will die like it did first. The injectors get starved from the top end running short and it dies.
Running rough and hard to start is from starving the top end of oil. You got air in the system. The knock could be an injector, but I would like to hear if you find any water in the pan.
Darin 99 ranger 97F250 66 fairlanes
"TheBeast"1997F2504x4dually4.10's,160k,140VIDM,HPX,4-5"dp, S366 turbo w/wicked wheel, AFE, elec. fuel,rosewood stage ones,php hydra,arp studs, comp springs, smith brothers push rods, adrenaline hpop,riffraff res,melling lpop,180 tstat,6.0 fan and IC,trucool,coolant filter,scan gauge,lots of other gauges,racer x valve body and billet converter, upgraded trans, F550 leaf springs,SD dual tensioner upgrade, cold ac mod,OBA,38gal