Carburetor CFM 360 5.9 Magnum Recommendation.

anything from 650 to 750.

personally i'd rebuild what you have and run it. unless you hate how it performs and it's crapped out, it's cheap and quick and will get you back on the road and enjoying the car.

if you were into upgrading and spending money, i'll throw my rec for an eddy AVS 2 650. or a small holley with vacuum secondaries, which there's literally a million to choose from.

a lot of carb selection comes down to not only the motor specs but also the rest of the package-- stall and rear end. but also, importantly, how you drive it. another parameter would be how comfortable you are with tuning carbs.