'73 450 SL EFI vs. CSI

[WCF]

New to forum!

It may be necessary to rebuild or replace my '73 450SL engine.

I understand that this year series engine is listed as having EFI. (I assume this means Electronic Fuel Injection.)

Should I replace it with a somewhat later 450 engine ('76-'80) that is equipted with CIS (?), will it be necessary to swap out some sort of computer control module for it to function?

Any input will be appreciated as to this swap out - or even rebuild.

Thanks..