W126 Engine Conversion
 

Has anyone put a 351 cleveland engine into a 1981 380 sel ?
I bought a 1990 420 engine to put in and it is in need of rebuild ( got ripped off ) I have a brand new 351 sitting in my garage and wondered if it is possible to fit in the merc.
I bought a 1984 500 coupe engine for a 1000 so I hope it all goes well .

It might fit more or less, but the cleveland is a very heavy motor. The extra weight will really overpower the suspension system. Mercedes never made any engines that heavy in that era so springs will not be available.

For the cost of making all the conversion you can no doubt find a good used motor. The benz v8s are very very rugged and seldom get worn out. Engine failures are usually due to being run low on oil or water.

Also the market value of a bastard conversion like that would not be good.

The market fot a stock gas engine v8 car is weak now anyway. You can probably buy a very nice one with a good motor and good cosmetics for less than installing your ford motor.

My advice? Buy a Fox Mustang to plant the 351 in, sell it, and reap the profits with your creampuff '91 560SEL that you'll enjoy with cash leftover .