support for subsequent installation against essentially the entire vehicle floor pan this is but one alternative for such a support another alternative is providing two such vehicle floor structural rigidifying supports as a two piece support with each being a support piece that is just a bit less than half the one piece support considered divided along lines paralleling the drive shaft channel in the vehicle floor pan that is such a two piece vehicle floor structural rigidifying support arrangement for subsequent installation of each against essentially a corresponding half or somewhat less if all of the drive shaft channel is not covered of the entire vehicle floor pan thus has each piece constructed individually hence a corresponding side conforming to half or a bit less of a floor pan and a further opposite dimpled flat side are provided for each of the two support pieces completed opposite sides or shells 14 and 15 for the desired vehicle floor structural rigidifying support have the flanges thereof each trimmed to leave one half to one inch thereof so as to form a reduced flange 14 a and 15 a on each as indicated in fig2 by a near periphery dashed line but one that is also.