19432393 Cylinder Head, Bare RS-X Spread-Port 

Special Order item

Un-ported bare head casting; Valve seats and guides included, but delivered uninstalled; As-cast paorts and chambers' Un-machined deck

The high-rpm airflow requirements of Pro Stock engines influenced the design of Chevrolet Performance’s RS-X spread-port Big-Block cylinder head design, which is used on the ZZ632 Deluxe crate engine. It uses a raised, symmetrical port design rather than the conventional Big-Block siamese design, for greater port-flow equalization. The heads are designed for large-displacement high-performance applications, where high-rpm airflow is a must for maximum performance.
They’re used with a shaft-style roller rocker system.
Assembled heads feature 2.450/1.800-inch titanium valves and beehive-type springs.

NOTE: Must be installed only on blocks with four valley lugs per bank.

RS-X Spread-Port Cylinder Head Technical Notes:

• Made from 356-T6 aluminum
• Will fit large-bore standard and tall-deck blocks
• 0.750" deck
• Intake part volume (nominal): 449 cc
• Exhaust port volume (nominal): 161cc
• Chamber volume (nominal): 70cc
• Intake flow: 481 cfm @ 0.787"
• Exhaust flow: 347 cuf @ 0.787"
• Rocker bar required
• Designed for shaft-mount roller rocker arms
• Designed for 7/16" pushrods
• Requires custome exhaust headers

Note: Typicle photos