Full Adder (FA) is an important component not only in arithmetic circuits, but also in designing and development in all types of processors. The performance parameter of the one-bit full adder has been implemented to increase the speed of the system. In this paper two Carbon Nano Tube Field Effect Transistor (CNTFET) based level restorers are introduced to the sum circuit of the branch-based logic and pass transistor (BBL-PT) full adder. The proposed level restorers eliminate the existence of voltage step which is presented in the conventional full adder [1]. T.V.Rao et. al proposed level restorer circuits that have used +1.2 V supply rail voltage [2]. By using these level restorers, we could able to achieve good delay performance. The proposed 1-BIT full adder is graded high as it has less power consumption with the conventional 1-BIT full adders. The performance of the proposed CNTFET based BBL-PT FA with new level restorer structures are examined using Cadence with 32 nm CNTFET technology files with a supply rail voltage of +0.8 V.