Starting my S1 XJ6 LS1 swap

Agreed: bumperless is best!

Could you imagine placing a bumper on this? Bumpers are for golf carts and tug boats.

fresh off the dyno. came in a bit lower than expected. no where to go but up.
needed a baseline and needed it to run/drive so i didn’t have to keep a foot on the gas pedal at stoplights.
was dyno’d in second gear. shop said they have seen too many ls conversion driveshafts come apart in 3rd on the dyno.
so add maybe 10-15 hp for not 1:1 gearing.
the stock intake and stock exhaust are killing the power. next will be an ls6 intake and some custom long tube headers and 350-375-ish at the rear wheels. then a set of heads.
when the shop puts up the video on their you tube channel, i’ll put up a link

on the dyno at about the 8 minute mark

got the windows tinted and the stock ls1 intake swapped out. next is custom headers.
that ls1 needs to breathe

That is one lump extremely well done.



If you need a Jaguar SI front bumper, you may want to contact Peter Crispen. I believe he may have one for sale.

thanks again for the kind words.
and i have the front bumper, i just prefer the look without it.

Example of new LS3 crate engine, 430HP, in XJ6 Series 1 engine bay.

More details here.

Wow, lots of connections!

Seems as though Boss Gunnar did it. I can live with it. I can read up here and visit regularly.

Wherever posted. A pleasure to read and admire…


I have a question regarding LS engines which I know little about other than there are lots of versions.
What made you decide on a LS1. Is there any advantage of this compared to other versions?
Regards, Jordy.

Check out the Kriss Motors web site. See the link on the post.

also search jaguatr-specialties. Andrew Weinberg, prop. Good guy and a bank of information.

The LS1 is the optimum of reasonably priced GM engines. Hight tech and lots of power. Fit nicely in the Jaguar bay.

Were I to do another swap, that is what I would chose. Not likely, at 89 and counting…

Heck, I messed up a simple task on my car.
Swap interior light switch in the drive A pillar.
Lost the two wires in the cavity!! Fish not working. other stuff in there to mess up. Remove the panel?? Perhaps…
when I get off medical light duty only…
Cataract removed from right eye!!r
Don’t bend well anymore…


i have done the carb’d 350 crate motor conversion already on an xjs years ago. wanted a new challenge with newer technology. TBI/TPI engines are harder to come by this day and age and aftermarket support is drying up. No shortage of LS parts to be had, stock or otherwise.
i chose the LS1 over the LS2/LS3 as i knew i needed the f body(camaro/firebird) accessory drive so it made sense to me to get a complete dropout engine/trans package from the camaro. i used a 2000 camaro ss z28.
this has some good general LS info if you are interested,

This video contrasts the original 1972 XK6 engine with the 2019 LS3, a crate engine from GM Performance with Holley front accessories, XAir OTR, Corvette-style cooling system, and custom radiator.

More details here.

out for a drive today. switched over the fuel tanks. it stalled at the next red light, started right back up. few miles down the road, there was smoke coming from what i thought was the dash(windows were all down).
pulled over, shut it off. didn’t see anything obvious.
another mile down the road, more smoke. seemed to be coming from the boot.
sure enough, pull over and smoke billows out of the boot when opened.
turns out all fuel pump and switching relay wiring is one big melted mess all the way to the 6 way valve.
i’ll post a pic in the next day or 2. i have/had it wired as above. posts 70 and 79
i have switched tanks before with success.
any ideas where to look first?
oh, and i do carry a fire extinguisher. fortunately didn’t need it, but it was close.

not sure what went sideways here. car was still running as smoke bellowed from the boot. had a few hundred miles on it.
i will be adding an inline fuse or 2. need to cut all this out and replace and start ohming everything out.

You may have noticed a recent post by goodoldgrandad (pre-XK), regarding a fire he experienced in his car. This was due to the unintentional grounding of the battery feed by a steel cable. Wonder if something like that caused yours.

From afar, I see the “hot” spot. Upper left corner of the last picture. A crimped splice of a solid brown wire. That denotes battery +, always hot!! I suspect a “high” resistance splice. prefer solder. Son differs and favors crimped.

+. to me the brown seems a bit light for the load of switching and pumping!!

Or simpler: Brown wire insulation chafed to ground!!! .

Lucky lady was with you!! Fuel loi8nes remained intact!!!


still haven’t looked into this much. so far i have simply cut out the melted mess and now have no relays or wiring to the pollack valve. the fuel gauges still operate off the dash switch. and the fuel pump works as well. just no way to switch tanks right now.

poking around the internet the pollack valve should only draw .5A and only very briefly when the internal motor is switching, and then back to off.

so with no power applied to the pollack valve, fuel still passes through one of the 2 ports to the fuel pump. i have not figured out which one as of yet.
i wired the valve according to this, Tank Switching Relay Updated Diagram.pdf,
well mostly. i did not use the A, B, or C leads. only D and E. as the fuel gauge worked and switched via dash switch, so no need to change to the pollack to control that. i did leave the A,B,C leads exposed. perhaps this was a source of unintentional grounding?
those 3 wires still look as new as do all wiring on the pollack connector.

so is it possible i wired the wrong relay pin 30 to ground?

is it possible i have a bad pollack valve?

my thinking so far is this, since the valve is normally open on one side, it would seem i don’t need to simulate the DPDT switch with the 2 relays. if i apply power to the valve with one single relay, it should move the motor to switch the valve. with the power removed it diverts back to normally open? still researching that option. may just try it.