On Tue, 11 Dec 2012 10:55:13 -0600, Steve Kraus
wrote:

Anyone with a lot of Briggs experience know if a 390323 carb be used to
replace a 490419 which is NLA? They look identical. Both for 8HP engines.
I suppose there could be hidden differences like the openings in the jet
but I'd think if both are feeding similar HP engines that would be alike
and I can always move the part or get a 490419 carb kit. I'm just really
tempted to solve the issues I've been having by replacing the whole thing.

Have called B&S or visited their web site?