engine knock/rattle 360

I checked my firing order twice but will do it again. If that is it i would be jacked!
But I doubt it since it ran ok (not perfect ) before .

I thought the exhaust sound like it was running rich , not quite crsp , so I started playing with the jetting and swapping carbs....that is when the noise started becoming prominent.

It could be that I leaned out the jetting too much or that the over rich jetting masked the
Detonation ?

I am not really sure what this car should sound like since everything is new ?