XXTREME 240 LS 1/LS2 Rectangle 3.898 Small Bore (SOLD IN PAIRS)


The XXTREME LS 240 small bore head will take your LS1, LS2, or LS3 to levels that fully CNC ported OEM heads can’t achieve. Back to back dyno tests show well known fully CNC ported heads fall 70hp short of this 240cc as cast monster. On identical engines, there is no comparison. Our small rectangle is a beast! 5.7 LS1 with moderate cams made over 605hp on pump gas.

Requires 3.898 bore minimum and LS3 intake rocker.

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  • Pro designed ports & chambers
  • 240cc as-cast port designed and tested in the USA
  • Ultra-smooth 356-T6 Aluminum Casting
  • 5 angle valve job
  • 63CC or 59CC Chamber size or additional options available
  • 11 Degree Valve Angle
  • Diamond honed guides
  • Built-in raised valve cover rail
  • Monster .750 deck thickness
  • Billet LS3 OEM Rocker Stand
  • For use with standard or 6 bolt pattern
  • Large spring pockets
  • Utilizes 2.08 intake valve and 1.60 exhaust valve (Larger sizes available upon request)
  • Multiple spring options
  • Assemblies include: 21-4N stainless 1pc swirl polished back cut valves
  • Machined and Assembled in the USA
  • Outperforms other comparable heads in the industry