22 may be secured to the bearing plate 11 for increased integrity of construction if required the apron 31 is secured to the cylinder block flange 16 by the fasteners 26 which as indicated above simultaneously secure the sump 10 to the cylinder block 2 the first outer box like beam member 20 extends rearwardly of the cylinder block 2 towards the transmission unit 17 the second inner box like beam member 19 is truncated between the cylinder block 2 and the transmission unit 17 the purpose of the second inner box like beam 19 is to stiffen the structure and suitably space the extension frame 1 in relation to the cylinder block side wall 6 it may be found in some installations that the second inner box like beam 19 is not required it may also be found that the first outer box like beam 20 or other constituent parts of the extension frame 1 or apron 31 may provide suitable mounting points for the engine and transmission mountings in use the apron 31 of the extension frame 1 is attached to the cylinder block 2 with fasteners 26 as previously described to lower attachment points the extension frame 1 is also attached to the cylinder head 14 at upper attachment points at or close to the top rail 23 by fasteners 24 the apron.