Trans Am is indicated by the T/A decal on 1970 Dodge Challengers. 

Dodge built the Challenger T/A to compete in both SCCA 

events and races in the Trans Am series. Street variants have a 340 cubic inch carburetted 

V8 and carry the Challenger T/A 340 badge. 

To compete in the same class as Chevrolet and Ford vehicles, Challenger T/As that 

were used in competition had their stroke reduced to 302 cubic inches.