Gear Ratio

[Swain]

What gears should I be running. I am going to be running a stock T56 6 speed in my 68. I just got my 9 inch housing and need to get my third member. What Ratio should I be running?

[Van B]

I currently have a 3:90. And am thinking about going to a 4:10.

[monza]

FUeL has 4:10 It's fun and maybe to fast out of the hole but who knows, 6th gear is pretty much useless, mellow high speed cruising.( mellow but very fast)

Here is a good post regarding it:
https://lateral-g.net/forums/show...ghlight=4%3A10

[6D9]

Need more info!

Rear tire height?
Cam specs??

[Swain]

Not sure what size im going with in the rear, I am trying to pick out what wheel i still want to run and what size 18x12 or 19x12

I was thinking 4:10 as well

Thanks for the help

[GregWeld]

Originally Posted by Swain

Not sure what size im going with in the rear, I am trying to pick out what wheel i still want to run and what size 18x12 or 19x12

I was thinking 4:10 as well

Thanks for the help

Think about this - Corvettes run 3:42's and six speeds

I'm running a 3:73 in a 427 small block - and Ford 9"

So agree with the above commenters - high 3's or MAYBE low 4's... There are websites that you can compare gear ratios - and speeds... and tire diameters... that might be somewhat helpful for seeing the speeds in each gear. I use Smokemup.com but that is a "pay" site.

It's not fun to have to shift out of 1st gear at 10 mph - which is 10 feet from letting out the clutch... I've had cars like that - it sucks.

Ask Mark or Charley what Mule and Jackass are using - and whether or not they like them?

[Vegas69]

Look at your intended application and normal cruise speeds in your daily driver and play with the calculators. You also need to take into consideration your engine. How large is the camshaft, what type of fuel delivery?

[Swain]

As for right now I have a 383 SBC but things can change I need to do some more research haha. The motors just a short block but I keep thinking of going to a BBC. Thanks for all the help guys I will keep you posted on what I figure out.

[GregWeld]

Swain --

I don't know how accurate this info is - but it's food for thought and some discussion with someone that knows a whole lot more than I do...

I was "told" that the best gear ratio for "street" driven cars is one that puts your RPM at Cruise speeds about 200 RPMS LESS than where your CAM starts to make some torque (not just some torque but where it's going to start getting with it).... as this will allow you to cruise just "off" this area of the cam and by just barely tickling the throttle - you start to hit a nice sweet spot. This is supposed to give good gas milage - but give you great throttle response.

I'm tossing this out - since you said you have a short block - but also that you might change to a BBC... so that CAM selection / torque RPM / Cruise RPM calc would be important and make a huge difference in the feel of the car.

So, as example - you have a Cam that is rated at 2000 - 6500 rpm... I'd figure I'd want to be cruising at 1800/1900 RPMS at ? 65mph? and calculate backwards from there using your tire diameter. Or build the motor - dyno it - and see where it starts making power?

[Vegas69]

I agree, you need to spec the motor and pick your tire size first.