I would not even consider a 325cfm port job on a street 400. It would never run great. Unless you did everything required to make a 400ci engine get the airspeed up in the port with a CSA large enough for 325-330 cfm.
Big cam, big CR, big carb, big converter and big gear.
Ken at PPR had about the best running 400 I know of. E heads were sand rolled to 290cfm with lots of velocity.
Heavy 2nd gen ran 9.30s. It did have a Gabby Warrior intake though.
I think you are far better off to not port your heads and spend the money on a set of 4340 rods and a 4" stroke forging while you are at it. 4.25 crank if you are feeling squirrelly.
Not TRW pistons either so you can get a good ring pack.
You could save some money with a sweet custom sft cam and not worry about needle bearings flying around someday.
I would not even consider using cast rods these days, your engine is worth too much.
Forget any 1050 carb, 950 for that matter. All you need is a nice 850 DP carb and it would be on the big side on a 400.
770 Street Avengers are junk.
This right here is one of the best carb deals.
https://www.jegs.com/i/Quick-Fuel/793/6-850QFT/10002/-1
Its a easy way to get a nice 850 DP. All you need is DP metering blocks, base-plate and bowls. You can even use a 750 base plate and this main body will get you a 830cfm carb.
You can always upgrade your port work later, roller cam if you want. But a solid foundation is far more important.