14 Bolt Gear Ratios? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HAMMERDOWN · 05-06-2002, 06:53 AM

I'm trying to find out what gear ratios are offered as standard on the GM Corp. 14 bolt FF. The only reference I can find is 3.73's, 4.11's, & 4.56's. Found me a rear for a steal, just didn't have time to inspect it. It's on a 74 (2 wheel drive 3/4 ton pickup). Preciate any knowledge that can be passed along. Thanks
JP

powermad · 05-06-2002, 11:00 AM

3:73 gears are the most common in a 2wd rig.
Although I got lucky and scored 2 14 bolts with 4:10's out of 2wd rigs.
My 73 C20 and 81 C20 Burb have 3:73 gears.
4:56 gears are generaly found in 1 ton rigs and they are usualy military rigs.

------------------
78 K5 on 3/4 ton axles.

HAMMERDOWN · 05-08-2002, 08:17 AM

Wound up baggin the 14 bolt FF for a mere $110. Overall, it's in great condition for the price. It's got 4.10 gears, not much slack, brakes are in good condition, and the R&P are both chip & burn free. Gonna take a little work, but nothing major. Now, if I can just unearth that DANA60 front, I'll be set.
JP

powermad · 05-09-2002, 05:58 AM

That's not a bad price, I paid $50 for mine Hee Hee.
I paid $200 for the D44 8 lug, $191 for the 15x10 wheels, $80 for new u-bolts (front and rear) and $20 for the u-joint.
Depending on what your shaft is the u-joints are ..
1310 series yoke 1 1/16" cap Napa #338
1330 series yoke 1 1/8" cap Napa # 447
When I start breaking parts all the time on the D44 then I will upgrade to a D60.
If the 14 bolt is from a 2 wheel drive the shock mounts will have to be relocated.
Other than that it was a bolt on affair.
I did it by myself in the gravel in 2 days.
Both axles.

------------------
78 K5 on 3/4 ton axles.

HAMMERDOWN · 05-09-2002, 08:36 AM

Right on powermad. Thanks for the info. Did you convert from a 1/2T to 3/4T? My truck is an 85 SWB, and my drive shaft is stock. Original axles were 10B front & rear (still got that weak 10B GM corporate on the front-busted, & I gotta 12B on the rear off a blazer). I'm already using an adapter ujoint on the rear. Am I lookin at a custom drive shaft for the 14BFF? I gotta 700R4 & NP208 Tcase. Yep on the 14B being off a 2 wheel drive. Wasn't sure if I'd have to relocate the shock mounts or not. Oh well, no big-E. Anyway-preciate anything you can pass along.
JP

powermad · 05-10-2002, 07:21 AM

Ya I went to 3/4 ton K5's are 1/2 ton LOL
I have an SM465/Np205 and I used the same shaft.
You have a 1330 series yoke on yours so it will require the Napa #447
That is why you had to use a hybrid joint, the 12 bolt has a 1310 yoke and the 10 bolt has a 1330 series yoke.
I did have to drop my T-case 1.5" though as the added 2" from the 14bolt had my rear yoke binding.
I am still not happy with the driveline angle even though I have no vibes.
But a lift is sitting in the garage waiting to happen and when it goes on I will be mowing the perches off and rotating the axle.
When I did the shock mounts I lifted one side with the fork lift till the other side was just off the ground and I compressed the shock 1/2" and tacked it on then did the same to the other side and then stiched them up.

------------------
78 K5 on 3/4 ton axles.

ponjohn · 05-10-2002, 01:03 PM

Are the 14 bolt rears commonly found on the cab/ chassis? The 10 bolt is from a dual wheel pickup, correct?

powermad · 05-10-2002, 02:44 PM

14 bolts are found on 3/4 rigs till around the mid 80's then the 14 bolt semi floater started to be introduced. The full floaters could still be had but I think they were classed as a HD 3/4 ton.
They are also found on 1 ton rigs, single and dual tire versions.
3/4 ton vans will have them as well but the axle is wider than what is found on pick ups, some want these axles as it makes the rear axle track width the same as the front.
there are no 10 bolt 3/4 or 1 ton rear axles.
those are a 1/2 ton deal and jeneraly considered to be junk.
However the Eaton rear axles that could be found in 3/4 and 1 ton rigs untill 1972 had a 10 bolt rear cover and a drop out like a Ford 9 inch axle.
But unlike a Corporate 10 bolt with a 8.5 ring gear the old Eatons have a massive 12.5" ring gear and are a full floating design.

------------------
78 K5 on 3/4 ton axles.

ponjohn · 05-10-2002, 05:57 PM

If I were to perform a conversion that would result in a factory appearing dual wheel truck, what one would I look for? I prefer the look that requires the fenders. Does anybody have a measurement for the correct rear back plate to back plate? Thanks in advance. john

05-06-2002, 06:53 AM	#1
HAMMERDOWN Registered User Join Date: Jan 2002 Posts: 6	14 Bolt Gear Ratios? I'm trying to find out what gear ratios are offered as standard on the GM Corp. 14 bolt FF. The only reference I can find is 3.73's, 4.11's, & 4.56's. Found me a rear for a steal, just didn't have time to inspect it. It's on a 74 (2 wheel drive 3/4 ton pickup). Preciate any knowledge that can be passed along. Thanks JP

05-06-2002, 11:00 AM	#2
powermad Hillbilly Hotrod Join Date: Nov 2001 Location: Oregon Posts: 69	3:73 gears are the most common in a 2wd rig. Although I got lucky and scored 2 14 bolts with 4:10's out of 2wd rigs. My 73 C20 and 81 C20 Burb have 3:73 gears. 4:56 gears are generaly found in 1 ton rigs and they are usualy military rigs. ------------------ 78 K5 on 3/4 ton axles. __________________ 69 K5, .060 over 350/465/205.

05-10-2002, 07:21 AM	#6
powermad Hillbilly Hotrod Join Date: Nov 2001 Location: Oregon Posts: 69	Ya I went to 3/4 ton K5's are 1/2 ton LOL I have an SM465/Np205 and I used the same shaft. You have a 1330 series yoke on yours so it will require the Napa #447 That is why you had to use a hybrid joint, the 12 bolt has a 1310 yoke and the 10 bolt has a 1330 series yoke. I did have to drop my T-case 1.5" though as the added 2" from the 14bolt had my rear yoke binding. I am still not happy with the driveline angle even though I have no vibes. But a lift is sitting in the garage waiting to happen and when it goes on I will be mowing the perches off and rotating the axle. When I did the shock mounts I lifted one side with the fork lift till the other side was just off the ground and I compressed the shock 1/2" and tacked it on then did the same to the other side and then stiched them up. ------------------ 78 K5 on 3/4 ton axles. __________________ 69 K5, .060 over 350/465/205.

05-10-2002, 02:44 PM	#8
powermad Hillbilly Hotrod Join Date: Nov 2001 Location: Oregon Posts: 69	14 bolts are found on 3/4 rigs till around the mid 80's then the 14 bolt semi floater started to be introduced. The full floaters could still be had but I think they were classed as a HD 3/4 ton. They are also found on 1 ton rigs, single and dual tire versions. 3/4 ton vans will have them as well but the axle is wider than what is found on pick ups, some want these axles as it makes the rear axle track width the same as the front. there are no 10 bolt 3/4 or 1 ton rear axles. those are a 1/2 ton deal and jeneraly considered to be junk. However the Eaton rear axles that could be found in 3/4 and 1 ton rigs untill 1972 had a 10 bolt rear cover and a drop out like a Ford 9 inch axle. But unlike a Corporate 10 bolt with a 8.5 ring gear the old Eatons have a massive 12.5" ring gear and are a full floating design. ------------------ 78 K5 on 3/4 ton axles. __________________ 69 K5, .060 over 350/465/205.

05-08-2002, 08:17 AM	#3
HAMMERDOWN Registered User Join Date: Jan 2002 Posts: 6	Wound up baggin the 14 bolt FF for a mere $110. Overall, it's in great condition for the price. It's got 4.10 gears, not much slack, brakes are in good condition, and the R&P are both chip & burn free. Gonna take a little work, but nothing major. Now, if I can just unearth that DANA60 front, I'll be set. JP

05-09-2002, 05:58 AM	#4
powermad Hillbilly Hotrod Join Date: Nov 2001 Location: Oregon Posts: 69	That's not a bad price, I paid $50 for mine Hee Hee. I paid $200 for the D44 8 lug, $191 for the 15x10 wheels, $80 for new u-bolts (front and rear) and $20 for the u-joint. Depending on what your shaft is the u-joints are .. 1310 series yoke 1 1/16" cap Napa #338 1330 series yoke 1 1/8" cap Napa # 447 When I start breaking parts all the time on the D44 then I will upgrade to a D60. If the 14 bolt is from a 2 wheel drive the shock mounts will have to be relocated. Other than that it was a bolt on affair. I did it by myself in the gravel in 2 days. Both axles. ------------------ 78 K5 on 3/4 ton axles. __________________ 69 K5, .060 over 350/465/205.

05-09-2002, 08:36 AM	#5
HAMMERDOWN Registered User Join Date: Jan 2002 Posts: 6	Right on powermad. Thanks for the info. Did you convert from a 1/2T to 3/4T? My truck is an 85 SWB, and my drive shaft is stock. Original axles were 10B front & rear (still got that weak 10B GM corporate on the front-busted, & I gotta 12B on the rear off a blazer). I'm already using an adapter ujoint on the rear. Am I lookin at a custom drive shaft for the 14BFF? I gotta 700R4 & NP208 Tcase. Yep on the 14B being off a 2 wheel drive. Wasn't sure if I'd have to relocate the shock mounts or not. Oh well, no big-E. Anyway-preciate anything you can pass along. JP

05-10-2002, 01:03 PM	#7
ponjohn Registered User Join Date: May 2002 Location: woodbridge, ct. usa Posts: 145	Are the 14 bolt rears commonly found on the cab/ chassis? The 10 bolt is from a dual wheel pickup, correct?

05-10-2002, 05:57 PM	#9
ponjohn Registered User Join Date: May 2002 Location: woodbridge, ct. usa Posts: 145	If I were to perform a conversion that would result in a factory appearing dual wheel truck, what one would I look for? I prefer the look that requires the fenders. Does anybody have a measurement for the correct rear back plate to back plate? Thanks in advance. john



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