E-TORQUE’s UNIQUE CYLINDER HEADS

Jaguar XK 4.2 Liter Upgrade Kit

This 4.2 Litre Twin Spark cylinder head is perfect for anyone doing a total engine rebuild since the engine will be removed from the car making it easy to change pistons.

With the CP-Carrillo® Forged Pistons in this kit, you will have 11:1 compression ratio. Your intake valve diameter will go from 1.875” to 1.950" and your cam lift will go from .375” to .421” (w Mild cams or .466” w Street Performance cams). It's a great choice for anyone looking to get a lot more power and better drivability from their original XK engine with a smooth idle and great bottom end torque!

You can choose between Mild Performance and Street Performance cams. Mild Performance cams will create sufficient vacuum for the SU HD8 carbs. Street Performance cams prefer Weber carbs or are best for EFI!

What is included in the Jaguar XK 4.2 L engine rebuild kit:

  • A fully assembled 4.2 Liter E-Torque Cylinder Head machined for Twin Spark operation - with shimmed buckets and ready to install

  • A set of forged custom CP‐Carrillo® 11:1 compression pistons

  • A stand alone Electronic Twin Spark Ignition System

  • Two Wire Looms and associated hardware to organize the spark plug wires along the cylinder head

  • Head Replacement Gasket Set including Cometic® Head, Cam Cover, Inlet & Exhaust gaskets

Notes:

  • Although it is not necessary, it is always good to replace the original crankshaft with a billet steel version. First - a new crankshaft will get rid of the rope rear bearing seal that causes chronic oil leaks, and second, old crankshafts do break when you dramatically increase the power of the engine.

  • E-Torque stocks piston sets for each displacement in one diameter - 3.415” for 3.8 Litre blocks and 3.640 for 4.2 Litre blocks. This leaves .0075” per side for bore cleanup on a reconditioned block. Should you require a custom size piston, they will need to be ordered from CP-Carrillo® in California. Their typical lead time for custom orders is 12 - 15 weeks.