Both are M130 engines. Basically the same in most respects. Most W113 engines had a camshaft unique to the SLs which accounted for about 10 more horsepower. There is some debate that some USA W113 cars were equipped with the tamer emission camshaft. The aluminum engine side supports on the W113 cars is different from the sedan supports (allows the engine to sit about 3/4" lower for hood clearance of the SLs). The W113 engines had a mechanical tachometer drive which was not used in the sedans. ( this tach drive can be added to the sedan engine). The front crankshaft pulley arrangement is often times different diameters on the W113 engines. Most other items are simply bolt on items or minor plumbing differences. (eg. alternators, AC brackets, possibly the distributor, linkage pivot on block, etc.
It is basically a straight forward and easy swap. It is a bit more work to make it exactly correct.
