It is well known that there are 2 different types of throttle bodies: the electronic one and the one with a vacuum reservoir.

Very little background story:
I bought my first real 2000 XJR today and I noticed that it still had the old type of throttle body with the vacuum reservoir..

So I wondered; what are the advantages and/or disadvantages of the older type? Is there really a difference in handling? I have the newer type lying around, but I also expect to have to replace wiring harnesses IF I want to swap it.
I'm not going to change or convert anything yet, just curious! I love my new XJR and want to keep it as original as possible .

 

The 1998/1999 XJR have AJ26 engines.
The 1999 XJ8 >onward has the AJ27 engine.

The first AJ27 was the NORMALLY ASPIRATED 1999MY XK/XJ
They continued the AJ26 engine in the SUPERCHARGED until the 2000MY.(at least here in North America)

The throttles (and engine management) are totally different and WILL NOT INTERCHANGE.

 

That's strange, because my XJR should be from 2000. I'll have to look up the month, maybe it's January or February, that they still had an old engine left or something?

 

You might want to look for the VCATS sticker next to the spare tire and confirm that the vin number on there matches the one on the door and dashboard.

 

The XJR had AJ26 engine up to VIN 878717.