ProMaxx 3152 XXtreme 255 LS1/LS2 Cathedral 4.00+ Large Bore 63cc Hydraulic Roller .650 Titanium Heads

Name: ProMaxx 3152 XXtreme 255 LS1/LS2 Cathedral 4.00+ Large Bore 63cc Hydraulic Roller .650 Titanium Heads
SKU: 3152
Price: 2561.99 USD
Availability: InStock

Fits Vehicle: LS1/LS2 Cathedral Port 4.00+ Large Bore

SKU: 3152

The XXTREME LS 255 cathedral port head utilizes an 11-degree valve angle to push it to the front of all cathedral aftermarket cylinder heads. Size for size, no one can touch this bad boy. If you have a 4.00 inch plus bore size engine and need cathedral heads, look no further to push your power to the XXTREME.

Features:

LS 255cc Extreme Cathedral Large Bore 4.00+ min 2.125/1.60 63cc .650 Titanium Pair
Requires 4″ bore minimum and LS3 intake rocker
Pro-designed ports & chambers
255cc 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 2.125 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

2.125/1.60

Flow Data @ 28″ water
lift	200	300	400	500	600	700	800
Int	145	220	275	325	347	361	363
Ext	60	115	180	215	230	245	252

Cylinder Head Options

Part No	Description	Valve Sizes	Chamber Volume	Max Lift
3150	255 LS XXTREME Bare	2.125/1.60	63cc
3151A	255 LS XXTREME 1/2 Assembly	2.125/1.60	63c	.650
3151P	255 LS XXTREME 1/2 Assembly	2.125/1.60	63cc	.650
3152	255 LS XXTREME 1/2 Assembly	2.125/1.60	63cc	.650
3153	255 LS XXTREME 1/2 Assembly	2.125/1.60	63cc	.700
3154	255 LS XXTREME 1/2 Assembly	2.125/1.60	63cc	.800

Part No	Description	Valve Sizes	Chamber Volume	Max Lift
3155	255 LS XXTREME 1/2 Bare	2.125/1.60	59cc
3156A	255 LS XXTREME 1/2 Assembly	2.125/1.60	59cc	.650
3156P	255 LS XXTREME 1/2 Assembly	2.125/1.60	59cc	.650
3157	255 LS XXTREME 1/2 Assembly	2.125/1.60	59cc	.650
3158	255 LS XXTREME 1/2 Assembly	2.125/1.60	59cc	.700
3159	255 LS XXTREME 1/2 Assembly	2.125/1.60	59cc	.800

Technical Specs

Combustion Chamber ……53cc-66cc
Weight …………………………66 lbs.
Intake Runner ……………. 255cc
Exhaust Runner …………..
Intake Valve Size …………2.125”-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