Your restriction will be found in the intake/cam.
There is NO plenum design that can/will keep up with a properly tuned ITB.
The cam will be the next short coming. 13.0mm lift is too small for even the most basic 86x86mm VE
There is NO plenum design that can/will keep up with a properly tuned ITB.
The cam will be the next short coming. 13.0mm lift is too small for even the most basic 86x86mm VE