I bought 440 source roller rockers. I have had a few issues getting them set up. There is more to just "bolting them on and go." First if you measure the shim packs that they sell for the rockers, measure them with a mic. you will find that they are .021 thick. Then take some 600 grit wet sand paper, and sand down the edges where they used a press to mass produce the shims,and you will find they are now 015 thick. I sanded 58 of those shims to get enought to set up the rocker arm to hit the valve stem in the middle. Next thing I found is if your stem hieghts are not correct, the roller on the rocker arm will not hit square on the tip. Which means that when the valve is opening the tip could roll off the valve stem. So then you are removing the heads and fixing, setting the valve stem hieghs back to factor. Then like i did, you take .010 off the deck of the block and .005 off the heads to true everything back up and you will have to order custom push rods. Even thought they are adjustable you want the ball of the adjustment screw up closer to the bottom of the rocker so that as the rocker arm rocks its not trying to brake the adjusting screw off. and for your question about valve covers my factory valve covers will not work becuase they will hit. I bought some mopar performance aluminum valve covers off ebay and they just do clear. I just thought I would let you know what you are up against before you buy the roller rockers. But they are much better than the factory rockers. If i had to do over again I would buy the comp cam steel roller rockers. Thats my opinion. Good luck