3.00 vs 3.54

[coletrain777]

I've got a 71 F-100 with a 3.00 rear end gear ratio (do I understand correctly that 71 is the only year that this ratio was offered?) and I was wondering, how much difference would I notice in acceleration/towing ability if I switched to a 3.54. The truck has a 360 with long tube headers. Just wondering if the swap would be worthwile, or would I gain about the same acceleration/towing ability if I did a cam swap and four barrel?

[coletrain777]

Bump

[ima71 trucks are older]

3.00 was offered all the way into the 80's and very common in the late 70's

It doesn't look like it on paper but 3.50 (3.54/5 is an aftermarket gear set and a stock 8.8 gear)) is a world of difference from a 3.00. Sure you can build up the engine, but you are straining the transmission and u-jounts alot less if your working the truck with 3.50's insteard of 3.00's.

[coletrain777]

I drive the truck between 70 and 80 on the interstate and I was wondering how this gear swap would effect my mileage/engine life. Also, by switching to 3.54 gears how much more powerful will my truck feel in comparison to adding hp (I know that there is a formula to figure this out, just cant find the info).

[averagef250]

85 would be about tapped out with 3.50 gears and 31" tires with a 2V 360.
Not at all comfortable.

If you like driving 80 you'd be best off sticking with 300 gears. Go 3.54's and an overdrive tranny is your best bet.

[coletrain777]

Would a cam swap help to make the 3.54 gears more usable (one that make power higher in the rpm range). I also could swap a 4bl intake and 600 holley on there it that would help as well. Just looking for the best possible set up for an all around daily driver that see both the highway and towing between 4k -7k from time to time.

[MaxKlinger]

What, how much, and how often will you be towing?

3.50 gears are a more common gear ratio for a 9" rear (are you running a 9" or a Dana?)

You've got a set of stones driving these trucks between 70 and 80mph. Mine runs great, but I don't ever want to take her over 55mph. Keep the revs low and the brakes cool.

[coletrain777]

I am running a 9" with a 3.00 gear. I can run 75 and feel no wobble, float, or anything like that, just feels like any other truck (plus I ride a motorcycle most of the year so driving an old truck doesn't scare me in the slightest Anyone else here run a 3.54 ratio or higher and run theirs at interstate speeds on a regular basis?

[ToughOldFord]

I have 3:73s with 31" tires. Cruises good @ 70. 75 truck starts to drift so I don't do that much. I've nailed 80-85 for passing, but I back off of that real quick.
I think I left my 100mph+ days behind me with my 20's.

[coletrain777]

Is it comfortable cruising at 70 mph for extended periods of time? Also, why do you suppose that your truck starts to wander at 75, is it worn bushings, kingpins, ect...? I am just wondering because I would assume that if everything was in good working order that even cruising at 85 or 90 wouldn't cause a truck to wander (although I still don't know a whole lot about these trucks).

[ToughOldFord]

Yep, it's fine @ 70. Could do it all day long as long as I can keep gas in it.
The whole front end suspension was shot when I got this truck, replaced a lot of it. It most likely wanders now due to me aligning the front end with a tape measure.
Still need shocks too...

[ToughOldFord]

FWIW I'm not quite hitting 3K RPMs at 70. It looks like 2,900 to 2950.

[MaxKlinger]

I'm honestly surprised so many of you drive so fast with your trucks 75-85mph).

As I've stated before I don't really plan on taking my truck more than 55mph. There's nothing wrong with my truck, I'm actually surprised at how well it handles and how smooth it runs for its age. However, I have several reasons why I feel this way.

1. Drum brakes suck. Period. They don't have the heat capacity or heat-shedding capability that disc brakes do. As a result, they are more prone to brake fade and having experienced brake fade and even brake fluid boiling in vehicles before, this is no fun. If you did a disc brake conversion, cool beans. I've got the same in the planning.

2. No overdrive! These engines, regardless of whether you have a straight six, FE, Windsor, or other Ford, were not designed to rev to kingdom come. Without overdrive and a very tall rear end ratio, I don't want to make a big engine scream. My brother's Integra redlines at 8,000 rpm. My FE 360? Not so much. Engine life will certainly be prolonged if I keep my revs down.

3. Even with the best in springs and dampers, these trucks will, at best, handle like a truck. This generation was known for poor handling in pickup trucks. There isn't the ability to make emergency maneuvers than newer trucks do, and they'll never be able to touch a passenger car. Therefore, I don't drive it like one. My Sable is a soft sprung passenger car but was designed at least to handle at highway speeds. The truck, not really.

This is just how I feel about my own truck. I'm not here to tell others what to do, since I'm sure just about all of you are more experienced than I am (hell, this truck is A LOT older than I am!). I just think our trucks have limitations on what they can do, and most of those limitations are not a problem at relatively low speeds.

I know I sound like an old guy, but I'm actually 23.

I'm sorry if I'm jacking the thread. I was just really surprised by what I was reading.

[ima71 trucks are older]

No overdrive! These engines, regardless of whether you have a straight six, FE, Windsor, or other Ford, were not designed to rev to kingdom come. Without overdrive and a very tall rear end ratio, I don't want to make a big engine scream. My brother's Integra redlines at 8,000 rpm. My FE 360? Not so much. Engine life will certainly be prolonged if I keep my revs down.

Nah, these engines were disigned in the pre double-nickel days of highway cruising. I've driven these trucks cross country, even FE equipped cars with 3:73/4:10 gears down highways at 70 for hours. let it breath once in a while.

Disk brakes are better then drums, but well maintained drums stop pretty darn good.

[theskytoucher]

Um i have taken my truck well over 100mph on stock suspension, rebuilt like 12 years ago but stock design!!! It was just fine i didnt get scared till i came up on traffic then i just let off and all was good!!!! I have a mildly built 351w and it was turning around 5000rpm i have 3.50 gears in the rear!!! T-18 Tranny!!!!
So it is possible and is very fun but work your way up to it!!! I drove the truck 75-80 for about 3 months before i tried 90 then moved uop from there!!!! Oh and this was all after 1 in the morning so very limited traffic!!! And the speed limit was 65MPH oops!!!!