Fresh 360 Valve Train Noise.....

If indeed the engine is clattering, then check the oil filter as said. Then I'd:

1. I'd do a compression check BEFORE anything else, to get a baseline of the cylinder conditions since the oil smelled of fuel. Worn lobes/lifters may effect these numbers.
2. Check the pushrod tightness as described and re-examine the valvetrain where you can see it.
3. Even if that is OK, you still could have the start to lobe wear and, with the use of what sounds like API SN oil with inadequate ZDDP, then IMHO the situation demands an inspection of the cam and lifters.
4. Pull out the block coolant drain plug(s) to drain the block before pulling the intake, to keep the coolant out of the valley/crankcase.