The Stovebolt Site Forums The Shop Area Driveline 3.55's with T5?

It all depends on the gear ratios in your T5, RB. Let me please give you an example: I have a 1959 235, a T5 and a GM 12 bolt rear end with a 3.07 ratio. It works fine. Here's why...the OEM 3 speed in the 1/2 ton truck had a 2.94 first gear and a 4.11 rear end which gave it a 12.08 final gear ratio. I have a 4.03 first and a 3.07 rear end so as you can see my final gear ratio in first is about the same as the OEM. On through the gears (the first 3 of which feel just like the OEM pickup gears) we go and in fifth my T5 ratio is .86 and so with my 3.07 rear end my overall ratio is 2.64. Now one thing I think is good to keep in mind is that if you had bought an El Camino or a station wagon with a 235 and a 3 speed with overdrive you would have had a 3.90 rear end and in overdrive the reduction would have been 30% making your final ratio 2.73. Awfully close to the same ratio I have. In a notably hilly or windy area I'll drop back to 4th and my overall will be 3.07 (since 4th gear is 1.00). Otherwise I'll zip along in 5th and at 60mph I'll be around 2000 rpm. Maximum torque for my engine occurs at 2000 rpm, by the way. Hope that helps.