New build spitting embers from headers

[dan468]

Just started up the 454 in my 68 pickup. Everything seems very smooth aside from some sparks or embers coming from the exhaust (open header). Could this be normal? The headers are new too. I wonder if the engine is sloughing off debris or there is actually metal to metal contact.

What do you guys think? Even if it was metal to metal, where would this occur? I'm experienced however this makes me a little nervous with a $$$ motor so I'm taking my time.

Thanks!!