Difference in these two heads
The 243 is plainly a better head and a great bang for the buck....Especially if you find a Z06 set with the light valves....
Found this on another site.
Casting Number 241
Head: 1997+ LS1 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12558806 (1997-98)
12559853 (1999-00)
12564241 (2001-03)
Combustion Chamber Volume: 66.67cc
Compression Ratio: 10.1:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches
Casting Number 243
Head: 2001 LS6 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12564243
Combustion Chamber Volume: 64.45cc
Compression Ratio: 10.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches
you will only find the sodium filled valves on the CTS-V and Z06 vette.



