Trying to get caught up with things after being out of muscle cars for 30 years is hard. I'm old school and all we had were 3 & 4 speeds. My last muscle car was a 1964 Malibu w/factory 4 sp. When cars started coming out with 5 speeds we all laughed. But now I see people changing to 5 speeds to make the cars more friendly on the freeway. Makes sense. But how do these trannys hold up to the abuse that can be dished out when going through the gears. Some of the old 4 speeds could take it pretty good. I used to love to grab second and the Malibu could chirp the tires pretty good when I hit 3rd, car was a 283ci but not stock.

 

i believe the t56 6 speed is stronger than the 5 sp.

 

If you want a 5 speed for an engine with any kind of h.p., use a Tremec TKO. There's a model 500 and 600, the numbers pertain to their torque rating. Aftermarket retro-fit kits are available. Stay away from the weak t-5.