For a long time I have believed that the 1300, 1500 and the 1850 dolomites have all used the same engine mounts, part number 158016, but that there was a dob of paint in them to indicate which were for use on a 1850 dolomite as these were softer mounts than the ones used on the 1300 and 1500 dolomites. I have only just discovered that the Official Triumph Dolomite Range 1976 Parts Catalogue gives a part number 149934 as being the engine mount for a 1500cc Dolomite. If you look at the Rimmer Bros site this states that the 149934 has been superseded by the 158016. Another interesting thing that I noticed in the Official parts Catalogue is that when the mounts are fitted to an 1850 engine they should also be fitted with a engine mount restrictor, part number 158586. Looking at the drawing in the parts catalogue this would stop / restrict the downward movement of the engine under shock but if the restrictor was turned around it would stop / restrict the forward movement of the engine and so prevent the fan hitting and damaging the radiator. Out of interest I also looked in an Official Triumph 1850 Repair Operations Manual that I have and in that it shows the restrictor plate fitted in such a position which would limit the forward movement of the engine.
A few of questions for 1850 owners does your car have a restrictor plate fitted, if so which way round is the restrictor plate fitted and finally do you think it makes a difference?