Since the 240 and the 740 share the same motor I presume that the exhaust manifold are identical. What is the situation with respect to the rest of the exhaust system The downpipe on my 240 needs replcement an probably the cat as well .I intend to go to a wrecking yard to get replacemnt parts and 740s coul be there in greater number than 240s. If I cannot get what I want off a 240, could I get the same from a wrecked 740 of the same vintage. My 240 is a 1990 and the O2 sensor is in the catalytic converter. It may be difficult to separate the cat from the downpipe so I may have to take both.