I have the original 4 spd that came with my 74 Firebird. The motor I built for the car (461 SD performance, Stump puller, blah blah, blah) will be close to 500 hp, don't know about the torque. I have been told that the Muncie will not last very long with this motor if I beat on it. I have been doing some research on the Tremec 5 or 600 and I am thinking that this is what I want for durability and mileage. I don't care about #s matching as the orig motor is long gone. My funds are limited am I am thinking of selling the Muncie and its Hurst linkage to help pay for the Tremec. My question for all of you is - what is the Muncie worth? What is the Hurst linkage worth? I would think that the condition is very good. I do not believe that it has ever been apart. I remember that it shifts smooth, no leaks that I can see. Its been in my storage shed for 9 years.