Beefed up My six, need more power to the Rear

Had a slant in a '72 duster/904. Cut the head .100, did very minor work in the bowl area under the valves at home with a dremel, put a super six 2bbl/intake on it from the junk yard and 3.55's. It was really spunky for a slant. It was a one legger but it would lay 50 black mark any time. But I said that to say this, there are different size exhaust manifolds, and we found one of the larger mouth outlets, and ran a true 2" pipe from there through a free flowing muffler. That was a difference we could feel. Also, we put a 10" converter in it and it took away performance. The motor had torque and moved better with a tighter stall.... let the torque push you instead of letting the horsepower pull you