Hi Brian, I should be ok on that front. I've modified some old heat exchangers by removing the outer tinware and inner alloy fins, essentially making j tubes. They're only going to be used whilst I have the engine on the running stand. When it eventually goes back into the bus, I'll be fitting a stainless system. I'm going to update my build thread soon and I'll attach some pics of what I've been up to engine wise.
Mike