ProMaxx 3165 XXtreme 260 LS3 Rectangle Large Bore 59cc Bare Heads

Fits Vehicle: LS3

SKU: 3165

The XXTREME LS 260 is the big boy on the block for as-cast LS Head technology. This head is for large bore power. Dyno results produce 700 HP plus on pump gas.

Features:

• 260cc LS3 2.165/1.60 59cc Bare Pair
• Pro-designed ports & chambers
• 260cc as-cast port designed and tested in the USA
• Ultra-smooth 356-T6 Aluminum Casting
• 5 angle valve job
• 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 2.165 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
• Accessory brackets may require different bolts
• Sold in Pairs

Flow Chart

2.165/1.60

Cylinder Head Options

Technical Specs

Combustion Chamber ……53cc-66cc
Weight …………………………66 lbs.
Intake Runner ……………. 260cc
Exhaust Runner …………..
Intake Valve Size …………2.165”-2.200″
Exhaust Valve Size …….. 1.57″-1.60”
Spring Pressure

Hydraulic Roller .650 max lift

Closed …………………… 155 lbs. @ 1.800”-
Open …………………….. 425 lbs. @ 1.150”

Valve Guide ……………Manganese Bronze
Valve Seal Material … Viton
Retainer Material ……Titanium or Tool Steel
Valve Job ……………… 5-angle
Valve Spacing ………. OEM LS3
Valve Seats ……………Hardened Steel

Spark Plug…………….NGK R5671A-7 3/4 GASKET SEAT PLUG

Fitment Details

Brand

ProMaxx