Thanks guys for the reply’s , good articles Skylarking. My engine has 74.5k kms on it now, has WP supercharger on it with W407 cam this includes upgraded valve springs and lifters. I don’t rev it to the redline at all, to be honest I’m considering a rebuild due to the dreaded piston slap, but once the engine has warmed up after about 4 to 5 kms it runs like a dream, doesn’t us any oil, with regards to the trunnion upgrade I’m just looking at reliability and removing the weak link. I presume the bronze bush would be the way to go as it completely removes the needle bearings ? If I don’t rebuild the engine I’d still like to do the trunnion upgrade.