What ratio do I need?

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350runner

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If your just using your truck to have fun I'd go 3.73 it will keep you in that fun power range your engine will like. What is your current engine profile and trans?

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Pender1

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If your just using your truck to have fun I'd go 3.73 it will keep you in that fun power range your engine will like. What is your current engine profile and trans?

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I've got a stock 305 and a SM465. But I finally pulled my melted rear end and found out that I didn't have 3.08 gearing that I thought I did, I had damn 2.73 gears. Got my 3.73's ordered and hopefully I'll have them installed by the weekend.
 

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I have the 465 and 3.73s and they work great for me.


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350runner

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Idk how I missed this. I really think you'll like the 3.73s their a mix between fun and a good drivable gear. And that chart isn't on spot

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Don5

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Idk how I missed this. I really think you'll like the 3.73s their a mix between fun and a good drivable gear. And that chart isn't on spot

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You will like the 3.73s. The 3.42s are a factory gear for a standard transmission. I also do not agree with the chart as well. BTW- I have a 350 with a 465, 3.73s and a 6 inch lift. I might change out to 4.10s but that will be in a while. I have no problem with this combo.
 

77 K20

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What is wrong with that chart? I think it makes perfect sense. In my case running 33" tires it shows if I had 3.42 gears like on my old Blazer I'd be at the very bottom of the yellow (less power). And my old Blazer was pretty gutless.

3.73 gears would be at the top of the low power range (I had this combo on my brown '78). Did ok, and never did try to pull a trailer with it.

4.10 gears is in the middle of the green balanced power. This is what I have now.

I sometimes wished I had 4.56 gears and the chart shows them in the bottom of the red for more power.
 

350runner

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Really don't want to argue, so I'm gone say and leave it at this... If your "ride" is "gutless" it isn't the gears.... it's your ENGINE. I've got a comp cams 260, tbi heads, cheap summit headers, duals, and a q jet and I can roast tires from a roll to 15 feet at least... Yea that's with 3.08s.
The charts not spot on because it doesn't factor in your current cam/ engine power range. That's what matters when choosing gears.

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The chart is accurate as far as the math is concerned. The color suggestion is just that, a suggestion, and can't factor in every possible powertrain possibility. The same chart could be posted on a Toyota 4-banger forum and then a Cummins-powered forum and people would say it's wrong. It's up to the reader to have some idea of where in the rev range their engine makes power and how that power is going to be used.
 

350runner

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@Pender1 any updates? Did you get the gears installed?

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Pender1

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@Pender1 any updates? Did you get the gears installed?

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Gears and install kit are ordered and should be here either late this week or early next week. I'm in the process of taking the old out and cleaning up the axle while I'm waiting. This truck has had a hard life as a farm truck, so I pulled the axle completely out and it's getting all new bearings/seals and a good cleaning and paint job. I'll make sure to take some pictures as I go.

And since I was asked elsewhere, I am planning on regearing the front axle as well, just not yet. Probably be after the first of the year. So for now I'll just have a 2WD truck, but having it mobile will let me fix a lot of the more immediate issues sooner rather than later.
 
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350runner

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Awesome! :)

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flyboy1100

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Gears and install kit are ordered and should be here either late this week or early next week. I'm in the process of taking the old out and cleaning up the axle while I'm waiting. This truck has had a hard life as a farm truck, so I pulled the axle completely out and it's getting all new bearings/seals and a good cleaning and paint job. I'll make sure to take some pictures as I go.

And since I was asked elsewhere, I am planning on regearing the front axle as well, just not yet. Probably be after the first of the year. So for now I'll just have a 2WD truck, but having it mobile will let me fix a lot of the more immediate issues sooner rather than later.

Thats what i should do with mine. My new rear gears havent arrived yet so there would still be time. Really would like some 4.10s but 3.73 would also be an improvement over my 3.42 with my old worn out gutless 305.

New engine first. I can regear the truck later if needed.


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77 K20

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Really don't want to argue, so I'm gone say and leave it at this... If your "ride" is "gutless" it isn't the gears.... it's your ENGINE. I've got a comp cams 260, tbi heads, cheap summit headers, duals, and a q jet and I can roast tires from a roll to 15 feet at least... Yea that's with 3.08s.
The charts not spot on because it doesn't factor in your current cam/ engine power range. That's what matters when choosing gears.

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I'm not here to argue either. Was just wondering why some said the chart is off.

You are right- once you do some engine mods or put a new engine in, things can be way different.

My results were from older tired bone stock engines. My Blazer I was talking about had quite a few miles on it, but still ran good. It was a 305.
 

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New engine first. I can regear the truck later if needed.


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A new engine... the dream that may never happen for me.
 

flyboy1100

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A new engine... the dream that may never happen for me.

Same, but i keep looking and hoping someday

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