[ERA Chas]

Forget calculators for 471 cubic inches.
What's making the little carbs 'work' is the crappy stock MR heads. At 471, those heads will be a major restriction and defeat the purpose (and expense) of expanding the engine size. The BT intake is also being wasted. It's over-qualified for your current job. You'll easily make 600HP instead of 500 your way.
Preferred method is get a set of stage II or III Ede or BT heads from the vendors here. 2.250" intakes wouldn't hurt either.
With better heads that cam will work with at least 600's and properly set-up, will have great driveability and top-end too. Get the carbs from the recommended carb shops on here and they will have correct bleeds, boosters, cams and all to work well.
I ran 650's (at 427 inches) with a bit more cam and Lovehamr runs 750's on a 482 with great results.
No street-driving problems and a better use of money spent.