Replacing an '80 motor with a '79

[FlyingSteve]

The motor in my 80 550E sounds horrible at idle... The bottom end sounds like it needs a good rebuild and I believe it to be ****ing oil from the gasket between the block and lower portion of the cylinders. I'm sure the bottom end needs new rod/main bearings but I'm not sure what else could be damaged as well. I have a good condition '79 550L motor sitting in my garage with lower miles and I was thinking about swapping that in rather than rebuilding the current motor.

I know that the '79 motor uses different carbs, so I was planning on swapping the head from the '80 motor on to the '79 so I can use my existing carbs... I would also need to swap the ignition components over because the '79 motor uses a points ignition system, compared to the primitive electronic ignition that is on the '80 motor. Furthermore, the '79 motor uses electric and kick-start. I was also thinking about swapping clutch covers to eliminate the kick-start.

Is there any problems with this that are not obvious? I have a complete engine gasket set so I do have a new metal head gasket to put on and other seals as well... I've used the kick-start to rotate the crank on the '79 motor so I know that it isn't locked up and, externally the motor looks in fabulous shape.

Oh and do these motor utilize studs or bolts for the head, and are they re-usable or should I get new ones?

Thanks!

[Guest]

For what you're doing the old head studs will be just fine. I'd leave the kick starter on it, but that's just my two cents...

[FlyingSteve]

Well, I originally wanted to use the '79 motor cuz of the kick starter, but when I realized that the cylinder heads were different I just decided to keep the original '80 motor. I am divided on whether or not I want to keep the kick starter and I very well may just to make this swap go faster.