ok this shocked me

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Brandon_l1000

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ok guys my truck has a 350 sm465 gm 10 bolt i have know all of this for a while the one thing i didnt know was what rear end ratio i had. i figured a 3.73 or maybe a 4.10. so i took the cover off tonight because it was leaking and i got the numbers off the ring gear and looked it up and to my surprise it's a 3.08. i counted the teeth and sure enought it is. to me this just seem small. so my question is is it?
 

HotRodPC

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Probably is Brando. Very common. This is why I jumped all over my GMC for $500 cuz it had a new crate 350 in it, and 3.73 gears. Imann's GMC K1500 also have wussy wagon 3.08 gears. 2 of the guys near the shop with K10's both HAD 3.08's OEM and changed them out. Oh, and my 85 K10 has 3.08's in it as we speak, it's still OEM.
 

Brandon_l1000

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Probably is Brando. Very common. This is why I jumped all over my GMC for $500 cuz it had a new crate 350 in it, and 3.73 gears. Imann's GMC K1500 also have wussy wagon 3.08 gears. 2 of the guys near the shop with K10's both HAD 3.08's OEM and changed them out. Oh, and my 85 K10 has 3.08's in it as we speak, it's still OEM.

it's just with that engine and transmission i expected something a little beefier i guess lmao
 

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Nope, that doesn't matter. Even I6 models came with 2.73 or 3.73. My truck that came with 3.73 was originally a 305 truck.
 

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I actually like my wussy wagon 308's :High 5:.

I dont know what your plans are for the truck but if you are daily driving it I would just leave the ratio. My last long trip in the truck I was getting 16mpg averaging about 65mph.
 

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I actually like my wussy wagon 308's :High 5:.

I dont know what your plans are for the truck but if you are daily driving it I would just leave the ratio. My last long trip in the truck I was getting 16mpg averaging about 65mph.

oh i plan on it and i dont mind that ratio i just figured it would be something different lmao
 

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Of course, more trucks come with the "standard" ratio than optional. What the standard ratio is for a given model year is directly related to how hard the gov't pushing for fuel economy / emissions / etc..

My old '80 K10, which was sold towards the end of the 70's fuel crunch, came with a 350, 465 & 2.73's.
 

bucket

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The "standard" ratio also depends on other options. My '79 crew cab has "standard" 4.56's because it was originally a camper special with a 350. The gear ratio is not listed on the option sheet since it was "standard".

However, I think the standard ratio for the basic half ton was 3.08's. I believe the 2.73's were actually an option.
 

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Of course, more trucks come with the "standard" ratio than optional. What the standard ratio is for a given model year is directly related to how hard the gov't pushing for fuel economy / emissions / etc..

My old '80 K10, which was sold towards the end of the 70's fuel crunch, came with a 350, 465 & 2.73's.

Yep, The 80 GMC 1/2 Ton 2WD I bought, RPO Code said, STANDARD RATIO, but didn't give the ratio. It turned out to be 2.73. Both 81s, the GMC and the Chery 1/2 ton 2wd trucks also both had 2.73, but the RPO Code didn't say Standard Ratio, is just gave the Ratio and the Code for 2.73. Sucked ass badly. Even friggin station wagons had 3.08's.
IMO, for a base standard 1/2 ton 2wd truck should be 3.42 with 3.73 and 4.10 as options. In a 4x4 3.73 should be standard with 3.42, 4.10 and 4.56 as optional. 3/4 ton 2wd should be 3.73 standard and 4.10, 4.56 optional, and a 3/4 4x4 4.10 should be standard with 3.73 and 4.56 as optional. But that's JMO.
 

bucket

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Yep, The 80 GMC 1/2 Ton 2WD I bought, RPO Code said, STANDARD RATIO, but didn't give the ratio. It turned out to be 2.73. Both 81s, the GMC and the Chery 1/2 ton 2wd trucks also both had 2.73, but the RPO Code didn't say Standard Ratio, is just gave the Ratio and the Code for 2.73. Sucked ass badly. Even friggin station wagons had 3.08's.
IMO, for a base standard 1/2 ton 2wd truck should be 3.42 with 3.73 and 4.10 as options. In a 4x4 3.73 should be standard with 3.42, 4.10 and 4.56 as optional. 3/4 ton 2wd should be 3.73 standard and 4.10, 4.56 optional, and a 3/4 4x4 4.10 should be standard with 3.73 and 4.56 as optional. But that's JMO.

That's odd, the '79 lists absolutely nothing about the ratio. Maybe because it's a different year. Or maybe the different assembly lines listed things differently?
 

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Bucket, was your 79 crew originally a 292 truck? All of the 3/4 & 1 ton trucks I've seen with a 292 have 4.56's as the standard ratio. Maybe that's a package? I dunno...
 

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i didn't think about the fuel shortage in the 70's but that make a lot of sense. I know what my gas milage my truck gets and to be honest i'm kind of glad it doesn't have 3.73's in it lmao
 

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That's odd, the '79 lists absolutely nothing about the ratio. Maybe because it's a different year. Or maybe the different assembly lines listed things differently?

Maybe 80 was the first year for listing the ratio via RPO code. I'm almost 100% certain, 80 was the first year they installed the G80 Gov-Lock Bomb, so maybe the G80 RPO code went into play along with the RPO code for gear ratio all at the same time.

This is out of the 80 GMC I bought for $150 or $200, can't remember, but I sold the 12 bolt G80 Axle for $200 to a guy who swapped it into an 85 Peg Legger 2.73 truck 10bolt. He was tickled to **** to have a "Posi 12 bolt"
attachment.php
 

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bucket

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Bucket, was your 79 crew originally a 292 truck? All of the 3/4 & 1 ton trucks I've seen with a 292 have 4.56's as the standard ratio. Maybe that's a package? I dunno...

It was a 350 before someone swapped in a 454. IIRC, I found that the dealer brochure lists 4.56 as standard if equipped with 350 and Camper Special and 4x4. I think the 4.10 ratio would have been standard (with other options being the same) if it were ordered with the 400sbc.

Basically yes, it was a package in this case. But the ratio is not listed on the RPO sheet.
 

bucket

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Maybe 80 was the first year for listing the ratio via RPO code. I'm almost 100% certain, 80 was the first year they installed the G80 Gov-Lock Bomb, so maybe the G80 RPO code went into play along with the RPO code for gear ratio all at the same time.

This is out of the 80 GMC I bought for $150 or $200, can't remember, but I sold the 12 bolt G80 Axle for $200 to a guy who swapped it into an 85 Peg Legger 2.73 truck 10bolt. He was tickled to **** to have a "Posi 12 bolt"
attachment.php

Is that the truck you got the Olds motor mounts from?
 

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