How can I tell if I threw a rod on my chev 454 RV engine ?

You can remove your valve covers to inspect the rocker arms, and push rods. They should be all in place and not too loose. If you find nothing out of place on the top side of the engine, you will have to look to the lower end. From there, you may have to remove the engine to inspect the rods; I doubt you can remove the oil pan while the engine is in the vehicle.

First thing you'll notice is that your oil pressure will be WEAK. if you spun a rod bearing, it will have NO OIL PRESSURE at all. second, black smoke is a rich fuel condition, and if you threw a rod most likely it would damage the piston,cyl causing BLUE (oil) or WHITE (coolant). most likely it is either pushrod/upper valvetrain or ignition module causing a severe pinging/spark knock.It does'nt sound like a rod bearing to me.