Non matching cylinder head?

[Ash]

I have been in contact with a seller who has a 4.2 S1. The engine block number matches the original data plate but apparently the head is from a later car. Did the heads change at all during the life of these engines and is this likely to significantly reduce the value of the car?

Many thanks

[Gfhug]

Ash, is this an S1 car or S1 engine? Cylinder heads can have been changed during the life of a car, maybe a problem with the head gave reason to change it. Are you trying to get the car or engine at a better price because of this none matching? If it’s the car then the far more important thing is the state of the body. Rust!
Whether it’s an engine or car the important point is is it worth the money in your eyes? Maybe it’s a late XJ engine head to give larger valve?

Over to you

Geoff

[Ash]

Hi Geoff.

The car is a S1 4.2. According to the seller the head is from a later E-Type. Its not painted any colour, just bear alley. The car is a USA dry state example so the body is good. I am trying to determine if the head issue greatly effects the value before I consider purchasing and spending lots of time and money restoring it.

[Terry Sturgeon]

All XK cylinder heads fit all XK engines, some of the later ones require some mods to fit the eariier slightly shorter block. Visable external changes to the heads began by late '66 (approx), year of manufacture, when they stopped stamping serial numers into the head and stopped painting them. There is a letter cast into the center of the vally that changes with models, and a stamped boss at the rear with a letter/number punched in that was never recorded by Jaguar as far as we know. Subsequent obvious chages included slightly longer heads, provision of bosses cast into the head to allow the use of exhaust injection for pollution controls, and replacement of the three large bolts in the valley with cup type frost plugs. All cylinder heads AFIK have the part number cast into the underside but you don't see those without a mirror. There are probably more visable changes.

IMO if you are doing a top restoration - a concours car in effect, the original head will increase value. If you are doing a nice driver probably not. You can alyways paint the head, and some would restamp it - though that may be illegal, and certainly is if the car is represented as being original.

[Ash]

ok thanks Terry for your invaluable knowledge.
It 'maybe' ok to stamp a blank head but re stamping one would not be legal in the UK. As the head on this car is unpainted it may remain unstamped.