Well today my 455 olds started to have a knock down in the crankcase while going back to the trailer at the end of the day. When the knock started it lost allot of power and started to knock really bad, the engine has been running like a stripted ass ape until now, I idled the boat to where the knock wasn't so bad back to the trailer. I got the boat back home and started it to see where the knock was coming from and it died, siezed up. My guess is I spun a bearing on a rod? I dont have any oil restrictors or any oil mods, and I have been running the engine allot WOT for the past six years. The motor just had the heads rebuilt and I put a new timing chain, cam, roller rockers, hei dist. etc..., the engine had a problem last year with the famous milk shake problem after installing over transom bassetts, so I tore it down and cleaned all the milk out and revamped the water pressure problem to fix the milk shakeing. Now four weekends out this year another problem with the knock,(I think spun rod bearing). I have and 396 chevy truck block to build up but am in the process of making it happen. If anyone can give me some advice if this would be a major problem or just a simple pull the motor and replace the bearings I would appreciate the advice. Thanks.