Just installed new cam & hydraulic lifters in my 65 289. After adjustment and run-in I dropped to idle - zero oil pressure and loud knock from front of engine! At 1200 RPM knock goes away and pressure is about 50 PSI. Runs smooth and strong otherwise. I didn't pay much attention to the thrust plate when I reinstalled it and now I understand its supposed to go in only one way (not the idiot proof variety). Could this be the cause of the low pressure/knock? Thanks!