Contact John for prices , "JER. Hill" for his forum PM, bear in mind you supply the pistons and this is a relatively small batch of unobtanium, SRM have a similar product , they use a liner. John's will hopefully have nickasil lining if the casting is good enough quality.. i dont know exact numbers. I do know that these opportunities do not come up often, I waited 20 years to get a replacement for my worn Devimead barrels. John supplies suitable Fasteners
with barrel to mate with the head.
Also bear in mind the spigot sleeves are longer than stock to accommodate stroker cranks, crank case mouths will need material removed for big bores due to larger Spigot ODs.
My big bore set from the first batch have done around 17k miles with no appreciable wear. The bike has air filters, I have read elsewhere that Nickasil does not last well with unfiltered inlets., I dunno, but I am not taking any chances.