Just fitted up a set of (cooler) that is aston spec'd plugs

 

How much fun was the left bank?

 

Cylinder number 2 was a little tricky with the dipstick and #8 due to lack of space but overall it was pretty straight forward

))

 

any actual results other than depletion of the bankaccount ?

 

Parzival yet to drive it as I changed the plugs late on a Sunday night .

In terms of paying the outlandish Aston Martin plug price Cambo managed to order it with a Jaguar part number saving us half the amount .

 

What is that part Jag number for those plugs? Is that the 4.2L, what year is your vehicle and model, thanks

 

Spark plug info here https://www.jaguarforums.com/forum/j...-aj-v8-176996/

 

Finally managed a drive of the xk can definitely say the car is more responsive and smoother .
In terms of producing more HP I can say it feels a little stronger in the mid range but i doubt it's picked up any more horsepower at the top end

 

How did the old plugs look?

 

Slightly Brown to white

 

Picture not too clear to make out but "looks" like it might be normal especially if the "white" is really tan. Your insulators are really clean too, the ones I pulled from the Super V8 at around 60K were well corona'd.

 

Going off the pics we pretty much land in row 4
The Ok to lean/hot varieties