[W126 Coupe] RE: 560 into 500 swap - some issues

[Ian Gatenby]

I'm fitting the low mileage (37,000) engine and gearbox from my '87 560SEC
parts car into my '83 500SEC.  After pulling the wiring harness out of the
560 car, I decided to go the route of swapping over the 500 fuel setup onto
the 560.  Too much work to do with the wiring and too little time at the
moment (I've just taken on a role in publishing) to go the complete 560
engine management system route.  I recall reading on the forum years ago
that this was the way to go (but can't find it in the archives).

One problem I've encountered is the differences in gearbox wiring.  The 560
box has one less wire on the main connector (the round plug near the shift
lever on the box).  It only has four connector pins whereas the 500 box has
five.  There is also an additional connector pin that takes two wires on the
560 box about six inches forward of the shift lever (near the fluid line).
I was assuming that this related to the sports / economy selector?  The only
other difference seems to be an additional vacuum line that attaches near
the kickdown cable.

I don't want to use the 500 box - as it has always been a bit dodgy.

Can anyone help please - do I just omit the extra pin on the main socket and
cross my fingers - or do I have a fundamental problem here?  

Thanks

Ian
Sydney - Australia