I have arebuilt 85 302 HO.ran perfect it has about 3hrs run time ,around the block couple times and idle.today i started it ,it has a knock (LOUD),remove starter checked flywheel and starter all good.started it still knocks.removed valve covers started it, valves and rods looked fine,knock seems to be inside block.put valve covers back on started again NO KNOCK idled for 1min perfect took rpms up to 2000 ok let off went to 3000 ok let off went to go to 4000 when knock retured at about 3300.please help,thanks for looking

 

get it towed back to the shop you got it rebuilt at and have them come outside and start her up and then tell them they need to fix their mistake