 While all previous TRs were evolutionary designs developed from the TR2, the TR7 was an all-new design owing nothing but its model designation to the earlier TRs.While the TR7's unit body and wedge shape were advertised by Leyland as major improvements, these were offset by the TR7's return to a four-cylinder engine and a live rear axle.The TR7 was initially available as a coupé, with a convertible version being developed after the launch of the coupé.