Would eight American 18-inch guns outweigh Agincourt's speed?

Would an American battleship with eight 18-inch guns erase the advantage of a six-gun Agincourt?

Only if the comparison also overcame Agincourt's proposed speed advantage. More guns would still leave Britain able to claim that its ship could choose when to fight.

An American battleship carrying eight 18-inch guns could claim a heavier battery than a six-gun Agincourt. Britain could still answer that its ship was faster and could decide when to engage. American ships already often carried more guns, so an increased battery alone would not remove every British claim to superiority. The argument concerns competing images of technical leadership as well as tactical freedom. A decisive American reply would need to overcome the speed advantage too.