Rear end decisions
 

So I am trying to figure out what rear end to pick up for my 49' 3100. I know their are a wide variety of rear end options out there. Planning on a ford 9" rear end. 6l80e trans. 28.5" tall tires with a 500+ Hp 5.3l.

6l80e Trans gearing.

4.027
2.364
1.532
1.152
0.852
0.667


So I'm leaning towards 2.72 to 3.25 rear end. I compared everything to the icon thrift master. They are running about a 5.6 sec 0-60.
I am not sure where I want to be with the ratios. I just know I want it to be quick. I've been searching online and there just isn't much of a chart out there telling you want gear ratios are available. How does someone figure out what gear ratios are out there to choose from? Leaning right now towards a 3.00 but what else is available and should I do something different?

Re: Rear end decisions
 

With a 4.027 first gear I would think a 3:00 or a 3 :07 would be a performance gear ratio.
Take a look at the 6 spd corvettes and see what they offer for a performance package.
with the .66 over drive and a 3:0 should be a very good gas mileage package

Re: Rear end decisions
 

I had someone recommend a 2.72 but I have been leaning towards something shorts like a 3.00 or so. Everything will be sitting on an art morrison frame. I want to make this performance vehicle. I just don't want to go too short and be burning tired everywhere.

Re: Rear end decisions
 

I found this on Richmond gear site. Maybe it will help

http://www.richmondgear.com/index.ph...on-calculators


Bernie

Re: Rear end decisions
 

I would say, to pick the best rear end for you would be to do the math on a couple different rear ends. and aim for about 1800-1900 rpm at highway speed, that's how I picked my rear end ratio.

Re: Rear end decisions
 

I have been check out some different rear end calculators. My concern isn't so much the high way a cruising speed. However it is a huge perk. I'm almost more concerned about the bottom end. I just don't have any thing to compare to so it's hard to decide.

Re: Rear end decisions
 

I'm running a 29.75 rear tire with 323 gears in a 4l60E trans. I'm really thinking of changing to 373 gears. It just think the truck will be more fun to drive with steaper gears. at about 60 mph I'm only pushing about 1500 RPMs

Marc

Re: Rear end decisions
 

A 3.07 with a 6l80e very close to a 4l60e with a 4.09 rear end. It's all in that first gear. The 6l80e has a very short first gear. The Icon thriftmaster has the 4.09. It's a pretty sweet set up. I think they said 5.6 sec 0-60.