Originally Posted by
katze
anyone know whats the actual head clearance for a 353? is it the same as the 3sct, ie 0.3mm + 0.3mm?
if thats the case, it should be safe to not add anymore shims for 25% nitro right? even if you add 0.1mm of shimming, isnt it a bit too much, ie 0.7mm? top end will suffer?
You will actually gain top end when adding shims, but you lose a little bit of bottom end, there should be a total of .55mm to .60mm shims if using 25% fuel.