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Y-Block cylinder head machining and porting information. Due to the introduction of the aluminum heads:

 WE NO LONGER PORT Y-BLOCK HEADS.

                     

           ECZ-G lower port.                                             ECZ-G upper port.

                    

        Ported upper ECZ-G port.                                          Ported exhaust port.

                                      Typical flow @ 28" of water ECZ-G head.

Lift                       Stock                          Street Port                      Performance Port

                       1.927"    1.51"           1.94"          1.60"                   2.02"          1.60"

                               In.            Ex               In.               Ex                       In.               Ex.

.050                       31           26                 31               32                       36                  35

.100                     62           51                  64               57                      69                  64

.150                     90           72                 96                75                    100                  89

.200                   116            87               122                94                    129                108

.250                    133            94              148               113                   156                129

.300                   147          102              165               126                   177                 141

.350                  158           109             181               132                   196                  154

.400                   166           114             193               143                   212                 161

.450               170           119             207                 150                    218                 169

.500                  171           123             215               152                    227                 177

.550                  172            124                    not tested                        233                182

                                     

                                            Stock Exhaust port

                        

                           Intake ports showing direction of swirl

                       

                                                     Ported upper port

Intake flows up to 235 CFM @ .550" lift 28" test pressure along with exhaust flow up to 185 CFM result in horsepower potential approaching 475 naturally aspirated and 500+ for boost applications.

Street porting achieves increased power over a wide range while maintaining throttle response while race porting aims for maximum flow and horsepower.

Whether street of race porting, improved performance and driving enjoyment is available for the Y-Block owner.

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