I'm building a co2 powered car for one of my classes, and I have a quick question about aerodynamics of a shape through a fluid. I'm aware that a teardrop shape is the most efficient way to move through a fluid at subsonic speed, but since the design requires a largely rectangular body, therefore losing much of the gentleness of the taper, does this still hold true? Will the taper on the back of the fuselage confer any aerodynamic advantage?

TLDR is the top design faster than the bottom design, given everything else is constant?

My apologies for the MS Paint sketch, it's the best image creation software I have.