Dear Dan,
This is not an easy question.
There is no official list so far on what is interchangeable and what is not.
Basically all engines are more (230 SL, M127II totally ) or less (250 & 280 SL) unique to the Pagodas (the latter two engines have sedan siblings), at least for the engine mount arms, the tach drive and some more details.
Lots of tech parts like axle parts, brake and clutch parts, gearboxes, steering boxes, smaller stuff, lots of clips, hoses, clamps, doorlocks etc are interchangeable with the period sedans. Same holds true for the steering wheel and partly the rims (108 400 0002, 6J x 14H2 rim).
Basically everything else is unique to the Pagoda
as is
- any sheet metal parts, doors, hoods, etc.
- softtop, hardtop
- utmost of the interior, seats, doorpanels, handles, etc.
- most of the dashboard, instruments
- all outer chrome (I tend to say all ornamental stuff), weatherstrips
- headlights, taillights,
- exhaust
In summary,
it is better to have a spare part list for the Pagoda (the German fintail club is offering one for € 20.00) and look up the particular number of interest.
If it doesn't start with 113 but with 110, 108, partly with 111 or if it is one or the standard part numbers (norm part numbers like most screws, clamps, etc.) it is most likely a part not unique to the Pagoda.
Although MB passenger cars of that period are already designed by a modular construction system, I'd tend to say most of the parts you need for proper maintenance and rebuilt of our beloved SLs are more or less unique to the Pagoda.
Spark plugs, oil & air filters are of course not unique but more common also to other MB period cars.
Sorry please... :'(
Achim