E-Torque’s Unique Cylinder Heads

Jaguar XK 3.8 Liter Upgrade Kit

This 3.8 litre Twin Spark Upgrade Cylinder Head Kit is essential for anyone looking to significantly  improve their 3.8L XK Jaguar engine because this displacement suffers from large piston domes that deter spark advancement. The Twin Spark feature is designed to ameliorate that shortcoming.

This 3.8L cylinder head kit comes  with special CP-Carrillo® pistons to adapt the E-Torque Cylinder Head to the 3.8 liter’s block bore spacing.  This combination yields an 11:1 compression ratio.  The Twin Spark feature makes such a high ratio feasible, as it knocks off 10 degrees of spark advance. 

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). This is a great choice for anyone looking to get more power and better drivability from their original engine with matching serial numbers.

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!

The 3.8 Litre Cylinder Head Kit includes:

• A fully assembled 3.8 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

  Note:

  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. If 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.