Benson, for k swap you need ,
Engine 3-6k depending on what k
Engine harness - 850
K-pro with tune - 2200
Engine mounts - 500-700
Shifter box with cables etc - 300
Fuel lines and fuel rail- 300
Must for upgraded brakes, reconditioning
Of the k series engine and gearbox ,
Labour for drilling off stock b series
Mount etc there is lots more little headaches that pop up

Honestly for a b20 if you already have a b series
And you know where to get parts at good prices you can build
One for as little as 2500-3500 that's keeping stock head and tuned