*UPDATED PORTS* LS 243 CYLINDER HEADS GM LS1 LS2 CATHEDRAL PORT - PAIR (2 Heads) Bare

LS1 LS2 CATHEDRAL PORT - 243 CYLINDER HEADS

*NEW UPDATED PORT DESIGN*

Sold as a Pair - Bare. Machined - ready for assembly.

Suit the 5.7ltr and 6.0ltr 

These Cylinder heads are a High-Performance replacement to the GM 243 heads. All factory mounting points with the Performance of the 243 port and chamber.

You can use your existing valves & springs. 

Brand New Pair of genuine DETROIT RACING PRODUCTS Cylinder heads. 

Sold as a BARE pair. 

• Factory Valve Guides 0.500" OD x 8mm stem. - see photo of checking tolerance. 
• Hard 355-T6 Aluminium - Race Quality.
• 3 Angle Valve Seats - machined - ready for assembly
• Deck thickness:  0.360"
• Intake Valve size:  2.00" factory size*
• Exhaust Valve size: 1.55"  factory size*
• Intake Port:  212cc
• Exhaust Port:  76cc
• Combustion Chamber:  66cc
• Chamber Diameter:  3.890"

*Note: Seats can accept, however not ideal, the common aftermarket sizes of 2.02" intake and 1.570" (use Comp Cams part#: 6039-8 intake and 6048-8 Exhaust)

Installed Heights: 

Factory Valve 4.890" will give 1.750" Installed Height with Titanium/060 locator.

Factory Valve 4.890" will give 1.770" Installed Height with Steel Retainer/060 locator       

Flow Figures: in CFM - Please be aware of bore size when comparing CFM numbers.  A larger bore will always inflate flow figures as a result of the intake valve being unshrouded. Even 020" increase in the bore will inflate flow figures by more than 10%-20%. We recommend checking a CFM flow rate that is flowed on the same size bore as you intend to use. 

Flowed @ 28" on a 3.900" Bore. (LS1 3.898")

Lift        Intake   Exhaust

200        143        110             

300        194        142

400        236        165

450        251        171

500        263        177    541HP flow potential*

550        252        180    520 HP flow potential*

600        253        182    520 HP flow potential*

650        254        184

700        256        185

*HP figures are "Potential" based on Flow/Velocity calculations

We can supply assembled using: 

Single or Dual spring set up.

Use your existing factory valves.

We can supply aftermarket Stainless Steel valves.