Can anyone tell me if there is a reason why the standard combustion chamber on 132 and 138 is wider than the bore diameter. Seems a little odd.
I just did a quick measure job and it seems that the 138 heads are around 3.2" at widest point of chamber and 132 measures 3.1 to 3.15". I have a few heads and they look to be completely standard, certainly not showing any signs of polishing or chamber mods.