Oil consumption and ticking after cam swap?

My son and I installed a junkyard 5.9 magnum into a 72 duster last year for the Roadkill 3k hooptie challenge. It was out of a 2001 durango with unknown miles (rear end collision). We finished the install and took off on a 1500 mile road trip the same day. We made it with no issues and the engine ran great other than the distributor loosening up and shifting timing at one point. The event got rained out so we headed back home but then got invited for the filming of the show. I ordered a Hughes 2226-10 cam with matching springs and slammed it in so we could make a bit more power. After doing that, it seems to be burning a considerable amount of oil. It smokes out the pipes under hard accel and through the breathers on decel. It also makes an audible valvetrain ticking in the upper RPMs though this seems to be intermittent. I'm thinking I'll just grab another junkyard 5.9 (they are cheap and plentiful here) and swap the cam over, but I'm wondering what the heck happened. Seems like rings but I don't know why that would happen right after the cam swap and a leakdown test shows all cylinders <25%. Any ideas?