F100 Drivers, Tell me about your rear end (ratio)!

[Bummer72]

Now how's that for a catchy subject line.

Anyway, I'm looking for input from F100 owners, particularly those who have the 302 engine and Ford 3.03 3 speed transmission combo, but all are welcome to share:
1)What ratio rear end are you running?
2)Open or limited slip?
3)What size tires are you running?
4)What do you like or dislike about it's performance (in town, highway, country roads, commuting, occasional towing/hauling) and why?
5)What gearing would you change to and why?
6)Where have you purchased your gears, center units, etc.

Here's a fun site to play with to test out different ratios and tire sizes to see how the affect speed and RPM.
RPM/Speed/Gear Ratio Visual Calc

I'll start.
I have a 3.70 LS. It marches around town great, but 90% of it's use is going to be highway pretty soon, so I'm looking to have 3.00 gears installed. I got a center unit for a good price on craigslist, and that was what was installed, so I'm going to run with it for now. If I find it lugs the engine too much, I'll probably pull it and change to 3.25, which is what was stock according to my door tag. I'm running 235/75R15LT BFGs . I find 1st gear is pretty much only for pulling out from a stop, and second is only good up to about 20mph. That leaves from 20-70mph to be left to third gear, and when it's up there on the highway, it's howling along at 3000rpms.

[gregamorton]

with 3.00 gears second should be good to 60mph or more. I have run any thing from 2.47s to 4.11s with a 3 or 4 speed. If daily driven I would stick with 3.25s or higher. With the 3.00s you should be around 2000rpm at 55 and 2500rpm at 70mph with a 28" tall tire. If your engine is running good and not wore out it should pull the 3.00 gears fine for a driver but when pulling a heavy load you could drive slow 55mph and under in second to keep the rpms up for pulling power.

[gregamorton]

I looked up the gears in the 3.03 3 speed and it looks like running at 55mph in second gear you would be at around 3500rpm and would pull good if ever needed.

[Bummer72]

Thanks gregamorton,
My 302 will a fresh reman, and back on the road hopefully by the end of next week. They've rebuilt my 3.03 tranny, and are going to go over the 3.00 9" center unit and install it. I figured I'd have to wind out 2nd a bit if I've got weight in the back.
Any idea how pulling out from a stop will feel with the 3.00, without a load? I figure I'm going to be using the clutch a bit harder with those gears.
-Doug

[jzjames]

Pulling out from a stop at the light, and the Fiestas and Kias are probably gonna smoke yer ass.
Wouldn't ya say?

[Bummer72]

Haha, if I cared what my pace off the line was, I might be concerned about that...but I'm not
However, I don't want grandma honking her horn at me for putzing around, either

Another thought...does anyone know what new speedometer gear I should be using? (I'm just asking, but I'm also researching it online, too....).

[gregamorton]

I dont know what gear you need but I know that 73-79 dent trucks came from the factory on some trucks with the 3.00 gears. My 1978 f150 302 4 speed came with the 3.00ls. If your truck came with factory 3.25s then it wont be off by much. I always figure mine by my garmin gps at 55 and 70 and then know what speed to drive at. Hope you find what you need!

[Whateverman]

my ride's currently running a 5.0/c4 combo,its had a360/c6 and a couple of 351w's with c4's and np435's before ......

I've got a 3.50 geared 9in. with limited slip (with 350+ k mi. on it)
right now the trucks running some 31x10 1/2 's on it -partially because i was doing alot of highway miles and wanted to knock the rpms down a little (around 250 - 300 RPMS if i remember right) to help preserve my old engine (may it rest in peace) and partially because the lt 235/75's i have kicking around wouldn't hold air

I've also had a few other bumps with various gearing ( 3.25,3.50,3.70,4.10 & 4,56 (!)) both open and ltd slip and engines ranging from 300's to 302s and 360's & both manual and auto trans
- i've found 3.50 to be the best all around gearing -deep enough to tow and haul more than the truck should with out straining the motor much and the revs stay somewhat reasonable on the highway (somewhat)

i found 3.25's a little too steep especially with a stock 302,and didn't like winding out the engine at highway speed with the 3.70 & 4.10 trucks.....and the 4.56 truck (6cyl auto)- well,lets just say that highways were not even a possiblity...

[HIO Silver]

1)What ratio rear end are you running? 3.50
2)Open or limited slip? OPEN
3)What size tires are you running? 30x10.5x15s
4)What do you like or dislike about it's performance The NP-435's first gear is dang near useless 98% of the time.
5)What gearing would you change to and why? Not gonna change the rear gear. I'm planning to change the transmission to a TKO-500 or ZF-5
6)Where have you purchased your gears, center units, etc. Transmission will be from Tremec or the ZF-5 from a wrecking yard.

[Bummer72]

Just a quick note on my 3.00 rear end gears...downshifting into 2nd is not possible under about 25mph without grinding gears, unless you give it a double-clutch. My transmission shop says it's because the syncros can't keep up with the new ratio like I was used to. So if anyone changes to lower (or is it higher, I'm confused tonight) gears like my 3.00 with a 3.03 3-speed trans, I imagine you can expect the same.

[cdeal28078]

When my 71 F100 was stock it was a 302/3sp with 3.25 gears. I ran stock size tires back then,
It was a pretty good over all gear I think. I pulled several cars and trucks on trailers up and down the interstate with it and it did OK. Was not great but got it done.
I could also take it easy on a trip and get maybe 18mpg once in a while with the 3.25
clint

[HIO Silver]

1. 3.50
2. Open peg leg
3. 30x9.5x15LT Bridgestone Desert Duelers
4. Coupled with the NP435, first gear is useless. I can walk faster with it idling in gear. FEs are torquey... why do we need a first gear final drive greater than 24???
5. the plans are for 4.10s with Traction-Lok driven by a 5-speed. Final (over) drive ratio will be 2.79.. perfect for highway mpg and first gear will be reborn.
6. The 5-speed will be a Tremec TKO and the rear end gears by Randy's R&P.

[70shortbox]

MIne has been upped to a 351W, but still has the 3.03.
1. 3.25
2. Tractionloc
3. 255/70/15
4. Like the gear spread. Works very well with the mild engine. Dislikes, none really.
5. Wouldn't change for what I need.
6. My gears are original to the truck, but junkyards around here still have lots of 9 inch stuff.