Does anyone have experience with 305 swirl port heads? I am returning to small block performance after many years. I looked at the heads and think that the intakes will not flow well at higher RPM.

 

swirl port heads are intended for low lift applications only. the valves and ports are too small to support anything much above 5000 and will die above 5400 due to severe turbulance issues. they can be worked aroudn if you stick to lower lift longer duration type cams and don't try to spin them up too far.

later
tim