All of the 1993 & later M119 engines with EFI are the same dimensions, the innards are different! Should be able to swap w/o any real problems!! The 400E was a LEXUS fighter & came to US / Japan only. Beefed-up tunnel & suspension could withstand the extra HP. Have fun. Bet a 5 liter M119 motor will cost $6000 to $8000, from bone yard!!
The 400E/E420 had a M119.975 & the 500E/E500 had a M119.974.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)