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MTI Racing

MTI Racing GM CNC Ported Rectangular Cylinder Heads (LS3,LS9,L92)

MTI Racing GM CNC Ported Rectangular Cylinder Heads (LS3,LS9,L92)

Regular price $1,500.00 USD
Regular price Sale price $1,500.00 USD
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MTI Racing GM CNC Ported Rectangular Cylinder Heads (LS3,LS9,L92)

Price : $1,495.00 per pair

MTI Racing provides a CNC Ported version of the Rectangular LS3, LS9, and L92 Cylinder Head.

MTI Racing cylinder heads are precision CNC machined in house on our Haas and DMG Mori 5 Axis CNC machines to ensure that exact tolerances are maintained.

We have partnered with former NASCAR Specialist to optimize the available area of the stock casting out to 275cc’s ! Our LS and LT heads are cut in the exact same machine right here in Dawsonville, Ga. that has had Cup Series Racing heads developed in it.

Following each porting, each cylinder head receives a precision 5 angle valve job, not 3 angle used by many shops, to maximize flow and provide extended life of the cylinder head. To improve the performance of our valve job, MTI Racing also performs a contouring procedure on the exhaust valves seat using our Newen valve machine which blends the chamber into the narrow “throat” section of the port. Our development in this critical area is based off of countless hours of NASCAR cylinder head testing.

Note of Consequence: Don’t be fooled by competitors with flashy CFM numbers using larger valves, etc., that may be drastically larger than ours. Just like every chassis dyno will report your car at different power levels, so do cylinder head flow benches. Through our research, making a port bigger is NOT always better. Similar phenomenon occurs with CFM flow numbers. A particular head with slightly lower numbers may end up making MORE POWER due to the quality and direction of airflow. At the end of the day, MTI Racing is about making POWER, not selling CFM numbers.

Base price package includes porting your supplied cylinder heads. Upgraded valves and springs are additional cost.

Price $ 1,495.00 per pair

Customer must supply the undamaged heads to be ported. 



Intake Runner Volume         256 stock    275 ported

Exhaust Runner Volume         85 stock     91  ported

Intake Valve Diameter            2.165         OEM

Exhaust Valve Diameter         1.590         OEM

Valve Stem Diameter              8mm     

Valve Angle                            45 degrees                                                  


Flow Characteristics                                         


                                    Intake                                           Exhaust

Valve Lift        Stock          MTI  CNC                   Stock              MTI CNC 

         .1                 71                      73                       50                         52

         .2               182                    150                     105                       108

         .3               212                    227                     147                       148

         .4               262                    278                     177                       191

         .5               298                    314                     196                       223

         .6               307                    332                     204                       231

         .7               296                    332                     208                       235                                                                 

                                              .75  338


Note: Tested with 4.125 bore, clay entry on intake port. No pipe on exhaust port.

Untouched combustion chamber.


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