These Heads have more velocity, average flow and peak flow than stock LS3 cylinder heads.  Our LS2 flow is based on smaller valves (2.0/1.55) as opposed to the AFR (2.02/1.60).  This series is a stage III street/strip/race head and is designed for engines up to 6.6L.  The intake runner is improved by 57 CFM and the exhaust runner by 42 CFM.  We are not aware of any 15 degree valve angle, small valve, smaller runner head available that is superior to this one.  These heads are sold as new GM castings with standard GM valve train parts.  These heads are designed for stage III maximum flow regardless of the valve train parts used.  The RPM limit on the factory valve train parts is roughly 6,000 rpm with a camshaft maximum lift of .570.  Solid stem GM valves are used.  If you plan on raising the rev limit or camshaft lift, you need one of our upgraded spring kits.  Please note that the valve spring bosses are left in place for structural reasons.  Be wary of over ported designs where critical structure is needed. 

These LS2 and LS6 heads offer the following advantages:

1.  These castings can be used on any Gen III block.  The part numbers are not ground off like competing brands.

2.  New GM stock castings with no visual identification problems at a smog station.  No huge logos CNC'd onto the heads.

3.  22% more flow than stock. 

4.  An average flow greater than the AFR 225cc.  The ports are very active and produce excellent power for racing or high performance street use.

5.  High flow with stock valve sizes for a lighter valve train.

6.  Flexibility and choice of valve train parts. Stock conical springs to .570 lift or upgrade dual valve springs to .650 lift are available. A choice of hydraulic or mechanical roller spring pressures are also available.

7.  Larger seat and valve size combinations are available. Stock valves or upgrade hollow stem intake and sodium filled exhaust valves are also available in several sizes.

8.  We can provide refurbishment of any used product.

9.  Full machine shop services are available.

All airflow data is corrected data (Temperature and Atmospheric Pressure) at 28" of water.  Intake is measured with a shaped entry and the exhaust is measured with a stub pipe.  Adding a 2.055 intake valve increases the airflow on average of 5 CFM per lift point.  Polishing the runners can also add between 5-6 CFM at each lift point.

CombC=   65                                                        65                                                     65       

RunnerCC= 236                                                250   70                                             210  70

Valve =2.0 1.55                                                2.0   1.55                                           2.0  1.55

RLD CNC LS2/LS6              VS                GM CNC LS2/LS6              VS             Stock LS2/LS6

 Lift           E/I                                           I     E    E/I                                       I    E    E/I

.200  139  116  83%                                       147  111  76%                                    136 104 76%    

.300  200  151  76%                                       215  155  72%                                    195 135 69%

.400  256  184  72%                                       262  198  76%                                    237 157 66%

.500  298  204  69%                                       290  210  72%                                    260 169 65%

.550  308  211  69%                                       NA  NA   NA                                     NA  NA NA

.600  317  215  68%                                       307  218  71%                                    260 180 69%

.650  308  222  72%                                       NA    NA   NA                                   NA NA NA

AVG 261 186   71%                                      244  178  73%                                    225 153 68%

 RLD Performance, P.O. Box 890066, Temecula, CA 92589 (951) 676-4948, 9am-5pm Pacific Standard Time M-F,