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Discussion Starter · #1 ·
I have a 1995 C1500 single cab with a built 355, 2wd NV3500. I just installed a limited slip Yukon 3.73 differential in the factory 10 bolt. I’m good for now, but plans in the future are a pretty stout 383 with some spray. So I’m planning on that. What’s the GM 10 bolt good for power wise?

I found a local guy selling a GM 14 bolt out of a 2500 for pretty cheap. Probably a dumb question but Will the same Yukon limited slip fit?

For the upgrade, would y’all choose the 14 bolt or the Ford 8.8? Or is there a way to just beef up the 10 bolt? Daily driver/weekend cruiser truck.
 

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14 bolt is completely different, no parts from the 10 bolt will fit it.

The 8.8" Ford and the 30 spline 8.6" 10 bolt in your truck are roughly the same strength, and with the Yukon diff you've got a stronger assembly that any stock 8.8" ford with the weaker factory Traction-Lok diff.

I'd keep what you've got, add better aftermarket axles like Moser, Dutchman, Strange, or Mark Williams, and add a aluminum rear girdle cover and go with it.

It'll take more than a 383 on 300Hp spray to bust it then. If you do break it after that, I would not consider the 14 bolt or the 8.8" Ford as upgrades....go to either a 9" Ford, or Dana 60.

I'm assuming when you say 14-bolt, you are talking about the 9.5" ring gear 14-bolt with semi-float axles(6 bolt wheels), and not the 10.5" ring gear full-floating model (8 bolt wheels)
 

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the 8.8 is not an upgrade from the 8.5 30 spline.

the 14 bolt 9.5 is much stronger.

the diffs do not interchange.

on the street with radial tires I wouldn't be worried about the 8.5.
 

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X2 on putting a good set of axles in your 8.5/8.6 10 bolt. The axles are the weak link if you have a 30 spline center section.

I have a car that makes 800 whp all day on an 8.5 that has a 30 spline center with Moser axles. Been through Drag Week and 10k+ miles of driving and 5 sets of tires in that time frame at 3700lbs. You'll be fine with an axle upgrade. Axles are cheap in the big scheme of things IMO.
 

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X2 on putting a good set of axles in your 8.5/8.6 10 bolt. The axles are the weak link if you have a 30 spline center section.

I have a car that makes 800 whp all day on an 8.5 that has a 30 spline center with Moser axles. Been through Drag Week and 10k+ miles of driving and 5 sets of tires in that time frame at 3700lbs. You'll be fine with an axle upgrade. Axles are cheap in the big scheme of things IMO.
The GM axles are better than the Ford axles, and for the drag strip aftermarket axles are mandatory. On the street, not so much as the 95 models have 30 spline.

The 8.8 and the GM 8.5 share the same bearings. The 8.5 has smaller carrier bearings, same as the GM 7.5 and Ford 7.5.

The 9.5 is GM version of a Dana 60 and will take alot of abuse, but they tend to have heavy cases and thick axle tubes making them rather heavy.
 

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Discussion Starter · #6 ·
Great! I’m glad to hear I can keep what I have and just run some axle upgrades! Music to my ears a for sure. I know Yukon makes some axles as well. They claim to be 25% stronger than factory replacements. Anyone have an opinion on them? Mosers seem like the highest quality from what I heard/read. A little pricey though at 500 a set.
 

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Discussion Starter · #9 ·
Yea I’m definitely pushing the limits on the little NV3500. I wish someone made a beefier aftermarket option. I’ll look into that a little further. I can’t decide if a TKO 600 is my best option or swapping to a T56.
 

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Sm465, and a 4.56 FF C/C 14 bolt in stock form will hold up to 600ft/lbs clutch drops until the clutch gives out.

I went through 12 tires(dually)on a c30 one summer on a to give you an idea.

The nv3500 in my 94 1500 daily the TBI motor is only pushing 330ftlbs. 350ft/lbs is about as much as a nv3500 can handle when it is being abused. The back tires are my "summer tires" to allow for slip over grip to save the junk rearend when I want to have some fun.

This is one of my stock unmodified rides still running stock rims etc.
I have others that are cut up or modified and they will never run a 3500.



A SF 14 bolt (88-98) with a 3.42 is going to be a easy (almost) bolt in upgrade and what I would go with if I was looking for a bit stronger axle without alot more weight.

With 3.42 ratios you do not need overdrive and can run a wider range of direct ratio transmissions. You can swap your hubs in the front and have a correct bolt pattern all around running factory rims.
 

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Sm465, and a 4.56 FF C/C 14 bolt in stock form will hold up to 600ft/lbs clutch drops until the clutch gives out.

I went through 12 tires(dually)on a c30 one summer on a to give you an idea.

The nv3500 in my 94 1500 daily the TBI motor is only pushing 330ftlbs. 350ft/lbs is about as much as a nv3500 can handle when it is being abused. The back tires are my "summer tires" to allow for slip over grip to save the junk rearend when I want to have some fun.

This is one of my stock unmodified rides still running stock rims etc.
I have others that are cut up or modified and they will never run a 3500.


A SF 14 bolt (88-98) with a 3.42 is going to be a easy (almost) bolt in upgrade and what I would go with if I was looking for a bit stronger axle without alot more weight.

With 3.42 ratios you do not need overdrive and can run a wider range of direct ratio transmissions. You can swap your hubs in the front and have a correct bolt pattern all around running factory rims.
The SM465 may be strong, but for a 1/2 ton 2wd street cruiser, or a street/strip truck it's a complete loser for a host of other reasons....extremely poor gear ratio spreads....and just try to speed shift one of those, it's not gonna happen with internal parts that heavy and slow to move
 

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Sm465, and a 4.56 FF C/C 14 bolt in stock form will hold up to 600ft/lbs clutch drops until the clutch gives out.

I went through 12 tires(dually)on a c30 one summer on a to give you an idea.

The nv3500 in my 94 1500 daily the TBI motor is only pushing 330ftlbs. 350ft/lbs is about as much as a nv3500 can handle when it is being abused. The back tires are my "summer tires" to allow for slip over grip to save the junk rearend when I want to have some fun.

This is one of my stock unmodified rides still running stock rims etc.
I have others that are cut up or modified and they will never run a 3500.


A SF 14 bolt (88-98) with a 3.42 is going to be a easy (almost) bolt in upgrade and what I would go with if I was looking for a bit stronger axle without alot more weight.

With 3.42 ratios you do not need overdrive and can run a wider range of direct ratio transmissions. You can swap your hubs in the front and have a correct bolt pattern all around running factory rims.
The SM465 may be strong, but for a 1/2 ton 2wd street cruiser, or a street/strip truck it's a complete loser for a host of other reasons....extremely poor gear ratio spreads....and just try to speed shift one of those, it's not gonna happen with internal parts that heavy and slow to move
That is why you put a splitter behind it. Watson or gear vendors depending on what you can find. A 25% reduction splitter with solenoid shift will be like this.


3.58, 2.68
1.70, 1.27
1.0, 0.75

My watson with .72 between a sm465 and np205 will end up running these ratios.
3.58, 2.57
1.70, 1.22
1.0, .072

I don't think the sm465 ratios are that bad for a truck transmission.
You have a burnout gear that can allow even a 4 cylinder to smoke the tires.
A take off from a stop gear.
A drive from 15 to 60 gear.
Then a cruising gear.

If you want a highway gear then you throw a splitter behind it and you have a very tough transmission for a fraction of the cost of a "race" transmission that you can rebuild in a shed.
 
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