While rebuilding my engine I had a number of parts HPC coated to try and improve on the high underbonnet temperatures. These incuded the exhaust manifolds and dump pipes (after port/polishing) and the fuel rail for the injectors. As well as replacing the det sensor I soldered the wires to it and then sealed it with a hi-temp resin so it can't corrode again. I also took a die-grinder to as much of the internal webbing that was constricting water passages as I could get to, especially towards the back of the block. I'm sure there are other things, but I'll think of them once the coffee kicks in.
