What is the difference between a 1971 280 SE straight 6 cyl. carb. engine and the very similar 1972 250 C. I see that the caburetor jet size is different. The 280SE and 250C designation is cast on side of respective cylinder heads. I assume there must be a different camshaft (valve timing) installed for different torque and horse power curves from the two engines. Any specific information about the differences would be appreciated, or where such data could be obtained.

If they're both carb'd M130 motors, then they're about the same, except for some tweaks to the emissions every year between 1968 and 1972.

However, a 280SE is supposed to be a fuel injected motor, so if you have carbs in a 280SE, then either the car is misbadged or somebody did an engine swap.

Having said that, there are four things to look at to get an assessment.
- On the distributor is a plate with a number. Get the number. Note that for some older distributers that number has a few letters in it.
- On the back of the camshaft is a number. You will need a small mirror to see it, since it's about 3" from the firewall.
- The motor number, it's stamped into the block a few inches above the oil filter housing.
- The numbers on the bits of brass visible on the top of the carbs.

Armed with the Technical Data Manuals (a great purchase for anybody with more than one vintage car), you can match those numbers up see what you really have.

-CTH

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The carbed M130 SOHC 2.8 used in the 280S and 250C is essentially the same. However, '72 engines built for the US market had reduced compression to comply with US EPA regulations mandating the ability to accept unleaded gas, which was only widely availible in regular-grade at that time. So a '72 engine might have 10-15 less horsepower than a similar '70 or '71.

Happy Motoring, Mark

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