Teaser 2766: Two by two

From The Sunday Times, 27th September 2015 [link] [link]

Animals board the ark in pairs.

EWE and RAM
HEN and COCK

In fact these are numbers with letters consistently replacing digits; one pair of the numbers being odd, the other pair being even, and both pairs have the same sum. The three digits of the number ARK are consecutive digits in a muddled order. All this information uniquely determines the number NOAH.

What is the number NOAH?

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