Cylinder head curly one!

I like the clean look of the early cam covers. It’s a good way to hide the head swap from the casual observer.

Ahhhh… The secret manifold is from a North American Series II 4.2L E-Type. it is barely visible in the attached photo. It doesn’t look that way on an E-Type, because it is buried behind two Stromberg carburetors and under all of the add-on hardware it took to make them pass the emissions testing. For years, I would look at these beautiful E-Types, bonnets raised at shows, only to expose the formerly beautiful XK engine swaddled in the most awful Rube Goldberg add-on crap of emission controls. I would often ask the owners why could you not eliminate all of that crap and bolt the carburetors directly to the manifold. They always gave me a horrified look and cast me away like the heathen Philistine that I was, and I never saw a car done that way. Of course, anyone who now owns a Series II car has likely converted it to the tri-carb Series I setup by now, so these manifolds are relatively plentiful and generally cheap.

I use the K&N equivalent of the WIX 99897, originally for 1980-1989 Subaru. I drew up the front and back plates in AutoCad, then had them cut out of 0.090" aluminum with a waterjet.

I used the same filter, drew up the front and back plates on a piece of
aluminum and cut them out with a saber saw. ;^)

Mike Eck
New Jersey, USA
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2

I have not touched a saber saw to metal since I discovered the waterjet.


Popular modification for Mark 2 saloons, is to fit a early (pre-1969) straight-port-head directly onto the original 3.8 Mark 2 block (so will fit onto any 3.4 or 3.8 block apart from the UK only 3.4 XJ block), and then use an INLET MANIFOLD from a 420 saloon, which of course fits straight onto a straight-port-head, but also accepts twin 2" HD8 SU carburetters.
You can use a Series 1 XJ6 INLET MANIFOLD as well, but gets fiddly around thermostat housing/top radiator hose whereas 420 manifold has no complications. With a Mark 2 - triple SUs don’t easily fit, without major modifications.

With an E-type installation, due to closed- bonnet clearance issues, you do need an E-type Inlet Manifold (as that angles carbies down a little) and short-neck HD8 carburetters, so be a bit careful about mix and matches.


That makes sense, I hadn’t thought about those later E-types since I have been focusing all my learnings on the Series 1. Mine is an aluminum dash 63 rust bucket. :slight_smile:

What all variations were there to the straight port head? Is the 420 Saloon straight ports the same as the e-type? Are there others? I will still run the triples most likely (I like the idea of fuel injection still for practicality on a car that I am going to drive a LOT).

I am still looking for one to either build myself or use as a core exchange for a Cat Claw head. I have a really good buddy that works on some incredibly rare exotics (think lemans gull wings and 1 of 3 in the world ferraris… etc at a place here locally called VRM) and he has offered to build me a head so thinking about taking him up on that but also like the idea of a Cat Claw just because they have spent a long time learning to make power out of these…

Hi Roger The unit in question isn,t far from you Its a 3.4 xj motor They were never sold in this country , so it must be a private import ive never worked on one My query is about the stud spacing and whether the head will go on to a 3.4/3.8 150 block . I recollect ,that on my last visit to davids The motor was in the paddock with an unmachined straight port on a 3.4 XJ type of block I cannot recollect if it had the two extra water ports, and hence the bulge at the rear. If the head studs line up ,then the machining required to close off the 2 INLET side water outlets is easy , Neil K says he can use the block , I know hes building a LWT- E type ,but cant see it any use on that project Will advise when i see the head Terry Hilton Australia

Straight port heads where on
XK150 3.4 S
XK150 3.8 S
E-TYPE 3.8
4.2 S11
MKX 3.8
MKX 4.2
XJ6 4.2
4.2 S2
3.4 S2
4.2 S3
3.4 S3

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I bought and evaluated I think every two-carb variant of the straight port inlet manifold family. My decision to use the E-Type manifold was driven by the fact that I knew I would be using manual choke 2" SU’s and its more pleasing appearance. The E-Type manifolds were finished to a much higher standard compared to the others. As Roger notes, the E-Type manifold carries its carbs lower so that they clear the bonnet. This might create an interference with the steering column in a RHD car.

Nope, works perfectly with RHD. No clearance problems with steering column.
Remember, E-types were primarily designed as RHD, albeit Jaguar was fully aware that LHD was their biggest market, thus really they were designed for both RHD and LHD, thus such a simple job (relatively) to convert a LHD E-type to RHD, and vice versa. Not like many other brands, that have great difficulty, if not impossible to convert.



Of those what all would have been a straight port that looks identical to the 3.8 Etype head? Trying to broaden my search to other matches.

Not 100% sure but would have thought all before the XJ6 would be the same !

Here is a few pics of a 1975 3.4 xj6 Engine , I am getting it ready to fit in my MK2 , Iam making it look like a 340 engine as much as I can , looking in from the bonnet they will look the same .
In the 3rd pic you can see the hole I need to drill and tap for the 3rd cap head bolt !


hi the third hole is drilled and tapped 1/4 whit tapping drill size is
13/64 To take a 1/2 inch x 1/4 whit SHCS . Looks like your last picture
answers my “curly” question It clearly shows the "bump "at rear of head
for extra water ports Looks like i,ll have to weld them up Thanks to
everyone for their input Regards Terry Hilton Australia

Thanks for the drill size terry , got some new 1/4 UNC SHCS’s , I was going to stick a drill in one of the other holes to get the size , have a tap on its way !

I found this list ,

and took a pic of a head I am just finding out about , I did not know what waterways it had , I do now !

You can find that info here, if you have the book:

Hi Ian and List The confusion started with a head not on my list stamped
7D I thought correctly it was from a 420. Its the same as your picture
but without the 2 extra water ports at back! Maybe some kind of
transitional casting It would readily lend itself to a 3.4/3.8 block if
the two unrequired water passages on inlet side were plugged off. I was
hoping the unseen 3.4 XJ head was the same , but after the many pics posted
I can see its not . The 7D 420 head i have has been butchered and machined
away I cant use it on an engine ,only for bits and pieces. Thanks to all
on the list and hello to some familiar names from years gone by Regards
Terry Hilton Australia

I can’t seem to post to JL so I’ll use reply to ask a question. I have to install the chrome under the windshield of my 150 roadster. I have never done this before, do I center the chrome and start putting it under the rubber at the middle or do I start at one end and work my way to the other side of the car? Any suggestions on how to do this would be appreciated.

Len Wheeler