I recently swapped the old 3.90 rearend from my '56 3100 for a 2.73 geared rearend. At the same time, I swapped the 3-speed for a T5. Combined, I get much better economy and can cruise at 70+ easily. However, the 235 doesn't have the torque needed for quick starts, so I'm considering changing the 2.73 to a 3.08 or 3.23. This will also allow me to run taller tires without sacrificing my already challenged torque. Does anyone know if either 3.08 or 3.23 ring & pinion gears are interchangeable with the 2.73 set from an '87 Camaro?
T5's have several different overdrive ratios depending on what they were in so your final drive ratio could be anywhere from 2.24 to 1.96---way too shallow for even a healthy V8. The factory overdrive set up for years was a 4.11 rear with the Borgwarner 30% OD for a final drive ratio of 2.88, perfect for road cruising. To get very close to this with yours (2.73 vs 2.88) LEAVE THE T5 IN 4TH GEAR, problem solved. Also the T5 is a wimp transmission as far as withstanding torque so using 4th means there is nothing going through any of the gears, just the main shaft, so it will hold up much longer for load pulling.
