Being a 280S it is a carbureted engine, which is quite different from the fuel injected one. Head and block are different, as well as the whole intake system. This reduces by quite a lot the number of parts that are interchangeable with your Pagoda. A 280SE would be a better donor car. I don't know what is parts availability and prices in your part of the world, but $4,000 seems to be high. If the car has a manual transmission and you want to convert yours to manual, it may be an opportunity though.