From stock 311's to 456 gears. (1 Viewer)

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Joined
Sep 28, 2004
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1,415
Location
San Clemente, CA
I know there is a trade off and with pros and cons to everything.

Sometimes it can be a bit confusing.

I know with the 456's I can push larger tires and change fuel economy, but will it help me make It up those long up hill stretches of highway here on the left coast without shifting down to 3rd gear?
Will my fuel economy encrease or decrease with the 456's installed?
This last trip from San Clemente, CA to Pismo Beach, CA approx 250 miles with the 60 loaded down, we achieved 16.9 Mpg.
Rebuilt 2f, 32/36 weber., heavy duty wires, excellent plugs gapped to 40,000th, timing is around 5 degress/retarded. Next is a MS box.

Back to the gears.
Can someone please explain what switching to 456 will do? The pros and the cons.

Thank you in advance.

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And what should the work cost per axel?
 
Contact a shop for costs. Axle gears are matched to tire sizes and engine power. 4:56 gears are a good match for 35" tires, but 35" tires are not a good match for that truck unless it's primarily used off road in soft stuff. If you want to get a first hand feeling what different axle gears will do to your power, just ride a bicycle and start shifting gears. Low gears give you more torque, high gears maximum speed up to the point where you've reached maximum leg strength.

This old chart is a good guide. The stock gears are 3:73 and the stock tires were 28". Match a gear to your tire size. The standard "bigger tire" used on a 60 are 31" and you can see that that combo just puts it in the yellow. 31s are a wee bit tall for the 2F and 3:73 gears except when driving on the freeway with a 4 speed- then they're just right.

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Okay, so...I don't know your rig, but unless someone swapped out FJ62 diffs
or re-geared, then you have 3.73 gears stock IIRC. The 62 came with 4.11s

Second, I think most folks would see 17mpg and say that's real damn good for a 2F.

What tire size? looks like 33's?

Moving to 4.56's will probably help with hills, it'll change the speed at which you
need to shift. But it's going to diminish your top speed a bit. So if you're "giving
it all she's got" on the tach in 4th...now, you may be going 75-80mph? That'll
go down with a shorter gear. (Shorter equals bigger number, taller equals lower number)

As was said above...usually it takes getting to 35" tires before the 4.56 ratio starts
getting thrown around. Go get yourself 2 FJ62 front third members (they end up
being in better condition than a 62 rear third member because they are used only
a fraction of the time in comparison) and swap em out to get your step down to 4.11s.

Oh yeah...and timing... 5º retarded???? Stock setting 7º advanced for sea level up to
around 4000ft, at which point you add more advance, so how's that working well? IDK.

Cheers!
 
I have 4.56 differentials with 33x12.5 tires. But I also have the H55F 5 speed transmission--which gives me an overdrive gear.

The 4.56 and 33" tires will make the gear ratio a little lower than stock. This may help you going up hill in 4th, but I don't think it will help your top end speed or your fuel economy.

I think the fuel economy has many factors, only one being gear ratio. As I "upgraded" my truck, my fuel economy slowly dropped. I used to get above 15mpg, now it is closer to 10mpg. Upgrades included: bigger tires, new differentials, 5 speed transmission, suspension lift, front winch bumper, rear bumper, roof rack.
 
Wow. Thank you all for all the info. Quite the dilemma. Not sure how, or to even proceed. $$$, isn't a huge issue as I'd rather only make a mod once, and doing it right.
The top half of my 2f was rebuilt about 4k miles ago at 112000, 33" AT, H55h, not my daily driver. DD pic below.
60 when traveling weighs about 7k. See pics. Will be driving it all over the US in near future.
Should I switch to a 16" steel wheel?

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16" wheel allows you to mount tires with a higher load rating (and thicker sidewall). D and E rated tires are considerably heavier (and burlier) than the C rated tires you have now but they ride a little more harsh too since the sidewall doesn't flex quite as much.

If sidewall injury is a historical problem- definitely get 16s with higher load rated tires. If your current tires seem to work well, stick with that. I've never had a problem with C rated tires on the pavement or sand or civilized graded dirt roads. I've had more than a few sidewall death strikes though when driving in the rocks (not really a road) with them though (BFG AT KO).
 
Great. I was looking for the higher load rating being that my truck will. Always weigh around 7000 pounds no matter what the terrain. Especially aired down to 12 psi in the sand.

Looking for a steel 16", stock lugs spacing, with little to no BS which will Allow me, if I so choose, to upgrade front calipers.
 
you would be better served getting rid of small weber and getting a racer65 carb.
What will that do for me? My 2f?
More power?
will that negatively edfect my MPG?
 
Should also mentioned if I hadn't that my 2f is desmogged, ceramic headers, larger SS exhaust
 
Is anything broken? Like really broken? By which I mean - can you get the experience you desire with the truck set up the way it is today? There are endless mod's possible, and if you can afford them, go for it. But for most of us I believe strongly it's about the experience. So far my 2F gives me what I need, despite the need to slow down alot on long mountain passes. But I always get there, eventually, and that's fine. A 2F can be made somewhat better, but it will never work like a V8. Your milage is awesome, for a 2F. Maybe just have a beer and enjoy what you have...
 
I have a rebuilt 2F with a rebuilt ASIN carb and a bunch of smog stuff on it + H55 5spd and I get about 13 MPG on the highway at 70-75 (flat ground) Getting 17 is awesome. I have a 1HZ on a pallet in my garage, so plan to move on from the 2F tho. :D
 
Is anything broken? Like really broken? By which I mean - can you get the experience you desire with the truck set up the way it is today? There are endless mod's possible, and if you can afford them, go for it. But for most of us I believe strongly it's about the experience. So far my 2F gives me what I need, despite the need to slow down alot on long mountain passes. But I always get there, eventually, and that's fine. A 2F can be made somewhat better, but it will never work like a V8. Your milage is awesome, for a 2F. Maybe just have a beer and enjoy what you have...
Nothing broke, but a new oil leak drooping down the inside of my rear drivers identified tire.. Not brake line, pretty sure in an axel seal.
She drove very well this past weekend once properly warmed up.
 
I have a rebuilt 2F with a rebuilt ASIN carb and a bunch of smog stuff on it + H55 5spd and I get about 13 MPG on the highway at 70-75 (flat ground) Getting 17 is awesome. I have a 1HZ on a pallet in my garage, so plan to move on from the 2F tho. :D
Nice, I'd love to swap in a Diesel.
 

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