Ford 9" gear ratio question

[hotrodtim]

Hi, I'm new to the site and just beginning to put together a 1951 3100 for a daily driver/cruiser. I just got the frame back from being sand blasted and am ready to start the Mustang II crossmember installation. I plan to put a 4-Link in it and found a Ford 9" rearend last week with a brand new unused disc brake setup already on it. I plan to put a 4.8 or 5.3 LS engine in it with a 4L60E transmission and need to know if the 3.00 gear ratio currently in the 9" will work or if there is a ratio that would be better for the more economical application I want. Also, this is a great site and I look forward to taking advantage of the collective knowledge and experience of those of you who have "been there and done that" with your classic Chevrolet trucks.

Tim

[BarnFind]

Welcome Tim !! - The 3.00 ratio is a good start. You definitely dont want to go any taller with an overdrive trans. I have run the 3.00 in a 66 Chevy shortbed, 350/350 and it worked great. If I would have put it behind an overdrive trans it would have made it perfect. Something else to consider is your tire size. I ran a 6.60/15 tire. Sean

[tmoble]

I have a different take on it. Most GM cars that had a 200 or 700 OD tranny had more like 3.40 or so gear. IMO, if you run a 3.00 behind a OD tranny it'll never get into OD till freeway speeds. Around town you might as well not have OD.

I have a 70 Chevelle with a 406 torque monster engine with a 200-R4 OD tranny and 3.73 gear. If I had it to do again it would be a 3.42 or 3.36.

OD with 3.00, only if you live at Bonneville.

[hotrodtim]

Thanks for the input guys. I just found an on-line calculator that I plan to try to see what it has to say.

[solidaxel]

Welcome from So. Arizona Tim,

With the electronic 4 speed you will not know the difference much in low gear except your performance will be limited. Around town your computer will tell the transmission where to be by your throttle position and speedo.
Are you positive it is a 9" and not a 8"?

The trans I have in my 53 is a 4l60E and I thought I needed a lower gear as the ratio I had was a 3:25 and I really wanterd to put a 3:89 in.......but that was before I drove the truck!!

I am very happy to say that I am glad I left the 3:25 to try it out!

You have the 3:00 use it!

If your truck does not do what you want it to do, throw more money at it there is a great selection of gears out there.

By the way I am running a tall tire 255x70-15

[hotrodtim]

Yes I'm positive it's a 9" and of the gear ratio. I am planning to run something in the area of 235/70/15's on the back and probably a little shorter on the front. I will probably take Solidaxel's recommendation and just leave the 3.00's in it and give it a try. If I don't like it I'll look further at other options at that point.

Thanks again for all the input.

[MrDude_1]

for what its worth, the STOCK ratio of alot of 4L60E equipped cars is 2.73.
the optional performance ratio is usually 3.42... not 3.73s or 4.10s... although they are popular mods.

so with a 3.00 gear ratio, you will have better performance then what alot of cars had stock with that engine/trans.

and btw, on a 99 LS1 camaro with 2.73s and a very large stall, a friend of mine hit 11.1s regularly.. by the time he got in the 10s though, he had a 12bolt and 3.73s... i wouldnt consider 3.00 gears inadequate for a 5.3 or larger LS.

[Jb55]

sounds like you have a versallies rear end that came stock w a 2.90 or 3.0 gear ratio. im running a stock 350 motor w 700r4 out of a z71 i liked the ratio the truck had whick was a 373 so i put in 370s which was as close as i could get. i also played with the calculator to get a idea of my freeway speed along with my tire height. good luck