I can pretty much guarantee that just about every maker of a 650 carb will get approval from someone on this list. Holley, Carter, Edelbrock, Demon, etc.

They all have their pluses and minuses. Being that you don't know carbs, a Carter is simpler than a Holley in so much as there is less you can fool with to mess up.

That said, unless you are going with a stock OEM replacement identical to the original carb you will need to mess with it. None of them are really properly tuned for your application.

So what's wrong with your original carb?