M116 to M117 swap

[bladerunner30]

I've got a 1990 420SEL with an engine that's getting a bit tired at 217k miles, it needs new valve stem seals, new timing chain and a few other bits and pieces. I've also got (sat on the garage floor), an M117 5.0 from a 1990 500SE (I'm in the uk).

I know it will physically fit no problem, but are the electronics between the two engines the same? Can I just drop the 5.0 engine in and will it work with the 420ECU/Ignition modules etc?

Cheers, Martin