350 upper rebuilt now very very loud engine knock

[ryanbenn1207]

Engine- 350 1975 era

I just rebuilt this engine due to stuck lifters, I replaced the lifters camshaft and timing gear and chain, I was working on this with my mechanic friend in his shop, well i came back one day after it was all reassembled to find he had adjusted the rocker arms without me there, this worried me because he did not know how to adjust the hydraulic lifters on a chev 350. It cranked up there was some engine ba noise but not bad, I loaded the blazer on a flatbed trailer took it home. I drove around in the snow for about 15 minutes befor emy old retread tires decided they wernt gona push the truck anymore so i parked it. I came back a week later after snow melted and heard the most god awful knocking from the engine bay, this has nothing on stuck lifters. I removed the valve covers and 4 of the 8 pushrods were spinning freely on the drivers side engine, the number 1 cylinder was loose as heck, you could move the rocker arms ALL OVER THE valve stem. I tightened the rocker arm down till pushrod became hard to spin but the noise is still here,

Is this a classic example of improper valve adjustment or could i be looking further down into the crank piston area?