My car was originally badged "HE" on the boot lid. I changed it to "V12" in the mid-nineties, wanting to appear more formidable.

What is an "HE" model, and what are the differences between it and other XJS designations?

Oh yes; the car is a 1984.

Submitted by silver007@shaw.ca on Mon, 12/28/2009 - 13:29

The SC , I believe is the Cabriolet model which have removable targa type tops. As far as I know all 80s and on models had the HE combustion chambers, this combustion chamber basically doubled the mileage of the V12 and may have saved the V12 and possibly Jaguar from extinction...The earlier cars 75 to 80 had no combustion chamber in the heads, merely a piston with a dished area to give the compression space., mileage of the flat head engine was bad to say the least... The HE combustion chamber was developed by Michael May, a Swiss engineer, this design was apparently used even in the latest 6.0 litre engine which ran till 1996 ( last engine produced) what a shame.. so many high end manufacturers are now producing large V12 power, some even turbocharged etc and giving massive power.. I guess a lighter V8 with a supercharger seems pretty good for Jag today. How long will it be ( as my son asks ) till they opt for a 5.3 or a 6.0 V8 with a supercharger. not long I hope...

Submitted by dougdwyer1@com… on Mon, 12/28/2009 - 08:13

The "HE" has the "High Efficiency" engine with the redesigned cylinder heads and higher compression, first offered in mid-1981.

After a few years, in 1987 or so, the "HE" engine was no longer considered newsworthy, so to speak, so the "HE" emblem was no longer installed and a "v12" emblem was used.

Cheers
DD