Is This A KNOCK?!

ASSISTANCE Stock Engine-Bay Components
1

i recently finished a swap in my car with a built block, port n polished gsr head, with stock valvetrain. When i start the car i hear a knocking sound coming form the head. When i give it some gas the knock fades out. I was told from someone that aftermarket pistons and sleeve will sometimes tend to give off a knocking sound. Is this true? would an actual knock get louder if you rev it rather than fade away? What factors does timing have to do with a knock?

i have not gotten my tune yet, im not going to drive the car until its done.

2

I think the term your friend is refering to is piston slap. where the piston has a little back and forth movement momentarily before all the metal is heated and properly expanded

If its coming from the head it not a rod knock. are you sure all your valve train is tight

and timing has a lot to do with knock, try pulling it back(retarding) if you think it is knocking