i just replaced the head gaskets, intake gaskets, put new rockers and rods in, new plugs wires and distributor, and cleaned all the grime off of my 94 4.3 vortec tbi. while driving it home which is about a mile it started knocking. the oil is new and filled correctly and timing is right. the knock im 99 percent sure its coming from the bottom part of the engine. ive only drove it maybe 10 miles since the rebuild and its parked untill i fix it. what are the chances the rod bearings cant handle the rebuilt top end and need replaced without having to get the crank machined? dont have alot of money and miss my truck. thanks very much for any input.