You could try Howard Enterprises in Indiana. I'm not sure about the Hercs but it was the only place I could find cylinder kits for the Budas. They have a lot of stuff for other engines. They don't sell direct but parts stores and shops can order. Check their website. There's also Hercano Propulsion.
I always assumed the 570 Super had dry sleeves too but I just checked in my parts book and they do not! They show a sleeve for the 298 engine but the 339 illustration shows a block without a sleeve. Learned something new today!!!
