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Last Update 8-20-23
Our 1988 XJSC goes LS, and with a 6-speed manual, of course.......

XJSC LS Upgrade, Part 1, below; 

Go on to XJSC LS Upgrade Part 2, Click Here

Go on to XJSC LS Upgrade Part 3, Click Here

Go on to XJSC LS Upgrade Part 4, Click Here

Go on to XJSC LS Upgrade Part 5, Click Here

Part 1

November, 2018   


Some of you may be familiar with my 1988 XJSC. This car was part of a major buildup (and multi part series of articles- XJSC-LT1-Project-Click Here ) some 15 years ago using a 1997 Camaro SS LT1 engine and 6 speed manual transmission. It was a great project then and gave me many years of enjoyment since, but more recently it was getting driven less and less. One major concern was technical- we’re located in California and this car (like all others in the state newer than 1975 model year) was required to be emissions inspected every 2 years,. While the build itself was legal (it complied with California guidelines), the engine itself, even though it was relatively fresh, had a harder and harder time passing that test. This is a known issue with LT1’s and high NOx emissions, made worse by a free flowing exhaust which reduces EGR effectiveness. Conversely, the newer LS engines don’t have these issues. And lastly, ever since we built our XJS-LS prototype some 10 years ago (with an automatic trans), we wanted to do, but never got around to actually building, an XJS with an LS/6-speed manual drivetrain. Hmmmm..............

As fate would have it, a low miles 2002 Camaro SS LS1 engine and T56 (6 speed manual) transmission had been sitting in the shop here for several years looking for a new home and the stars aligned. Just in case you're not aware, the 2001/2002 LS1 engines were the best of the breed sporting the high flowing Corvette LS6 intake and 241 heads, a great cam. and no EGR. This package (which was also used in the 2004 GTO) made anywhere from 325-345hp (I suspect purposely under rated by GM) depending on where you read. And with a good flowing air filter/intake and free flow 2 1/2" mandrel bent exhaust in its future, it is sure to be a ball to drive (we also have another trick planned that is sure to add even more snap- a 3.54 posi differential- read below.....)

Getting back to the car as it sat, the LT1 engine and trans package still ran and drove very well and was a strong performer, including an impressive (and convincing) final high speed blast for the prospective buyer who planned to use it in his 70’s Corvette. A deal was done and the LT1 package went to a new home.

Here's a pic of the new 2002 LS1 drivetrain waiting for its turn in the Jag….


At the time of this writing, the engine package had been properly prepped and was ready to slide into the car. We'll have further details on that in the next installment.

But wait- there's more ahead....... 

Other Upgrades Planned:

Due to age, other areas of the car needed attention, and for the front and rear suspension, major upgrades were the order of the day:

Rear Suspension-

The standard inboard rear disc brakes were starting to give problems with odd instances of dragging, and the diff seemed to be seeping. There’s really nothing to complain about as they were still original after 30 years, so well overdue for attention.  In that department, rather than work with that problematic setup, it made more sense to upgrade to a complete 94-96 XJS rear suspension that would have outboard discs with modern sliding calipers and also a more aggressive 3.54 posi diff (instead of the relatively lazy original 2.88 ratio). I’ll have a more detailed article covering all that’s involved in doing this- it’s actually remarkably straightforward…..

Here’s a pic of that suspension just as it is sliding under the car.


Front suspension-

While still seemingly ok, the front suspension wasn’t as crisp as it should have been and was mostly still sporting its original components from 1988. The steering rack was also seeping (no complaints though- it was 30 years old....), so that would need attention. Interestingly, I had planned to rebuild the front suspension some 12+ years ago and actually sent out a full set of parts (A-arms, steering knuckles, spring pans, etc.,.) to be black powder coated for the project. Well that never happened, so now it will.  We’ll use all of those parts as well as the upgraded suspension pieces we offer to customers: 1 piece German-made sealed for life ball joints, polyurethane A-arm bushings and steering rack mounts, new tie rod ends, and of course our 1" front sway bar kit.. And rather than send our original older-design steering rack out for rebuild, we’ll trade up to the more modern 93-96 XJS one-piece cast aluminum rack, made by ZF. The original is all cast iron and steel (assembled from several pieces), while the later rack is much more reliable and also saves weight. Interestingly the crossmember to be used is actually from a 1996 XJS. (Jaguar actually produced this crossmember from the onset of XJ6 production in 1968 all the way through the end of XJS production in 1996, virtually unchanged....). More on all of that later.

Here's a pic of the assembly going together- look at those shiny new bits!!!


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Talk to you soon,