Mike, I'm asking this because I noted the fuel rails and stuff around them were usually a pain to do and not exactly cheap. I am fitting Megasquirt on a euro 5.0 M117 and have fitted the intake manifold out of a Djet 4.5 M117. It was designed as an EFI manifold to begin with, they are plenty and cheap, and injectors and rails are a straight fit. Throttle body is much more accessible and fitting a TPS is much easier. See pictures here: http://www.peachparts.com/shopforum/showpost.php?p=2314508&postcount=16.

Fitting an M117 in a W114 has been done before ans seems to be an easy swap. The alloy V8 is lighter than the L6 and the W114 Chassis shares the same front subframe and other elements with the r107. So it's a matter of getting an oil sump, oil filter housing, exhaust manifolds and engine brackets out of a r107 560 SL. In such a trim your W126 5.0 engine would clear the W114 engine bay and bolt straight on the original front subframe. You can then upgrade rear diff, brakes etc. by using 450 or 560 SL parts which are plenty and be a direct bolt on to your car. You may even use your W126 first gen. diff and brakes, I think they also would be a direct fit.

A Megasquirted euro 5.0 V8 W114 Coupe: that would be a very nice car, and you could have it look as if Mercedes did it!