In my 51 Chevy, I have a 56 Chevy rear end behind my 235 with a 5 speed. Right now I have a 3.55 gear but was wondering about changing to a 3.08 or a 3.36. My 5th gear is a .72. Is anyone running these combinations that could give me some idea of mileage and performance? Thanks for the help. Bill
I'd stick with the 3:55 before I went numbericaly lower. Actually I'd look at going higher with that combo.
I had an o.t. chevy truck with a set of 3.08's in it, and 32 inch tall tires. Swapping to 3.73's improved both my performance and economy. I'd look at maybe getting a set of 3.73's, or 4.11's with that t5.
When i built my old 53 chevy, i used a 235, T5, 56 chevy rear with the 3:36 gears. On the highway it actually lugged at 60 mph. Cant remember the exact rpm but it was under 2k which was great for the life of the motor. But, around town it could have really used more gear. I really think both mileage and performance suffered with the higher gearing. If i did it again id either run 3:55 or 3:70, with my choice being the 3:70. Tony
A lot to consider here. How is the engine built? How tall are the tires. A .72 is an overdrive gear. 3.55 x .72 is 2.56 final drive. Unless you are running a short tire, you're gonna lug that 6 cyl. A 3.73 may be a better choice depending on the rest of your set up.
Lower highway gears can put a strain on the motor. Lugging a motor with any load will hammer the main bearings to the extent that the bearing half end will squeeze in & contact the crank surface
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