Thread: gear ratio

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I'm new here and beging a project on a 1967 chevy C-10.
I need to know a good gear ratio for a 283. right now I
have a grany four speed with a 4.11 rear end. I run 3 grand
running down the highway at 60.

http://home.tampabay.rr.com/1bking/c...calculator.htm

is a calculator site that you may find helpful.

Don Shillady
Retired Scientist/teen rodder

Leave the rear end, put in a 5 over trans, S10 or Camaro. 70% OD gives you a top gear about like 3.08's, with lots of dig around town.

What size tires are you running?

A larger diameter tire may do what you want and will probably be cheaper . . . not to mention easier.

Measure the diameter of the tires and compare one against the other as a factor of percentage.

Figure as well the percentage factor of a gear swap you're contemplating so you can make a direct comparison.

Generally speaking - and I'm sure the math police will correct me if I'm wrong - a 3.50 diff compared against a 3.70 makes for about a 5% change.
A 30" diameter tire compared to a 28" diameter tire is roughly 6% different.

All of which means that making either change will change the engine rpm the percentage gained by either the gear swap or tire change.

If you pull a trailer the car trans might not be heavy enought the ideal heavy duty trans is a clark 5 speed, has and od and is heavy enough for a one ton, you would normally start it in 2nd , first is a granny gear. there was an article about the clark a while back in one of the 4 x 4 magazines and what is require to put them in. chevy had a bigger bell housing for the farm size trucks that would take a 12 " clutch, you never would wear it out in a 1/2 ton.

If you want cruising speed at a lower rpm, a 3.08 will take you down to 2,250.

timothale--a 283 isn't gonna hurt a Camaro 5spd. That Clark 5spd weighs a ton and uses a huge U-joint and the clutch won't take high RPM. Don't do it!