There is nothing wrong with a rv 440. They can be built like any other 440. A cast crank can handle 600 hp all day. Some of the 70's blocks are actually stronger than the early ones, with much thicker main webbing in the block. Check out 440 Source for more info.
Usually the water pump needs to be changed to a car type. The heads are usually smog style and are only good to 3500 rpm to make any power. The exhaust manifolds are horrible. Other than that its good for a performance rebuild.
but lets be real, any head he ends up with are better than what it comes with, and the other "conversion parts" can be had for the cheap, especially on moparts forsale section !!! also check out 440source.com if you haven't already, I picked up a 1/2 price passenger side water pump because the holes going to the block were cast too small, about an hour and 3 beers later I have the right size holes, super smooth and good to go !!! also check craigslist, I picked up an older edelbrock TM6 intake manifold, dirty as hell with a seized carb up top for $50, cleaned it up chased some threads, good to go, this is all for my 400 build, keep in mind A BIG THING 440's are wider than the 383/400, and the 383/400 with 1 7/8 headers is already a tight squeeze
I gasket matched the openings of the water pump housing and the block to make sure everything flowed well
Absolutely nothing wrong with an RV 440...great building block ( and cheap compared to earlier ones) for a performance build. And like was mentioned earlier..452 heads are the same ports as 906 but with hardened seats for unleaded gas
This is a motor home 440 I just freshened up for my Son's first car. The oil pan, motor mounts and water pump all had to be changed to passenger car parts from the motorhome/van configuration. It's just a cruiser for now. With EFI.