14129 - 14 Westerbeke Heat Exchanger. Westerbeke 40 / WPDS WESTERBEKE 40 - COOLING SYSTEM - FROM 1975 Westerbeke 40 / WPDS WESTERBEKE 40 - COOLING SYSTEM - TO 1975 Engine: W40 or W-40. This part has two configurations sold as the 14129CN and 14129-14CN. Take a look at the pictures to assure you're purchasing the right one. Both are approximately 14 inches long, but the hose configurations are quite different. They assuredly are NOT interchangeable. Call us with any questions on this part. We will not ship this product until we have talked with you. 14129-14 and 14129-14CN are the same part, both with a Copper Nickel bundle. Read Less