Putting together a big bore/big stroke motor? You are going to need a serious set of heads to keep up. Put too small of heads on a nice engine like that and you will make a bunch of torque, but the horsepower will fall off way early. Big engines need big airflow. This is where the RW 2020 comes into play.

The RW 2020 takes the cross section out to 1.800" from port entry to bowl & valve throat. Consistent through the entire runner. If the cross section is not enlarged, the air speed gets to high, and will choke the port off. This head flows over 300 cfm and with excellent air speed. Exhaust valve is opened up to 1.610" to keep up with the increased intake flow.

RW 2020 includes everything the 1900 does with upgrades of:

Intake valve seat replaced to accomodate larger AV&V 2.020" intake valve.

AV&V 1.610" exhaust valve.

Intake port cross section opened up to 1.800" from port entry to valve bowl and throat.

Same options as the 1900.