As I mentioned above, Redback make cores for trucks and HD off road gear (tractors, dozers, etc) and sell through radiator shops just like Natrad, etc.
My 'local' bloke was going to do it (my tanks and anew core) but I haven't as yet.
I couldn't afford the time off the road as I'm on call 7 days/week and SWMBO works and we only had the Patrol and 130, but as of the last couple of weeks we are now a 3 car family and I'm scaling that business back, so I have the Patrol to fall back on when the Landy is off the road now so hopefully it will be done soon.

