The engine that is currently in our Tiger has bronze heads, that were donated from the spare engine in my basement. (the originals were in rough shape) So far it hasn't skipped a beat.
The engine that I have in my basement is going to get equipped with the alloy heads that are on the shelf

. This one has domed pistons and we have scored a set of brand new sodium filled exhaust valves with guides. We will completely dismantle and overhaul this unit then install it in CF-MAD when it's ready.
Andy