My '85 Burb has a 3:73 ratio 12 bolt in it,and it appears original,despite the "facts" stating GM stopped using them earlier in the '80's...its a K10 ,six lug,700R4 with a 6.2...
CK5
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1989 v10 blazer axle ratio swap
- Thread starter Jamcc85
- Start date
With a gasoline engine? That takes the cake.
My diesel burb also had that combination, aside from using a normal 10-bolt. Not sure who at GM thought it was a good idea to run those gears on a diesel half ton with stock size tires.
I'd rather have 3:73's than 3:08's any day...
My '81 G-10 van had a 10 bolt 3:08 in it originally,but the side gears chowed the diff housing up after 138K,so I got a used rear axle from the salvage yard I hung around at for free --it was a low mileage one from a Beauville "window van" that had a 400 SB--unfortunately it turned out to be a 2:73 ratio axle...
The van will now go 60+ mph in first gear before it winds out,and can bury the needle at 85 in second!..
It lugs pretty hard going uphill at 65 mph with 235/75 /15's on it..taking off from a standstill on a steep hill sounds like your trying to power brake it...it needs a low range!..
My '81 G-10 van had a 10 bolt 3:08 in it originally,but the side gears chowed the diff housing up after 138K,so I got a used rear axle from the salvage yard I hung around at for free --it was a low mileage one from a Beauville "window van" that had a 400 SB--unfortunately it turned out to be a 2:73 ratio axle...
The van will now go 60+ mph in first gear before it winds out,and can bury the needle at 85 in second!..
It lugs pretty hard going uphill at 65 mph with 235/75 /15's on it..taking off from a standstill on a steep hill sounds like your trying to power brake it...it needs a low range!..
In a gasser, yes. But I'm tired of using O/D at 35mph. I'd need 35s to make my 3.73 rig happy on the highway. For cruising, anyway. The 3.08 rig is much funner on the road.
FWIW, at least in 1988, V10 Suburbans could only get 3.42 or 3.73 axle ratios, I would expect the same up to 1991, but axle ratio options are not in those brochures This seems to hold true for what I've seen, if it's a fuel injected half ton four wheel drive, you are almost certainly going to find 3.73's.
The trucks may have been different (1987 only obviously), and I can't find the same for the K5's, but I'd expect those two ratios only as well during the fuel injected era.
The trucks may have been different (1987 only obviously), and I can't find the same for the K5's, but I'd expect those two ratios only as well during the fuel injected era.
Did the diesels have different options?
6.2's got less options: 3.42 or 3.73 in R *or* V10's.
Gassers still had a 2.73 and 3.08's in R10 Suburbans.
Weird, I would have expected the higher gearing in the diesels.
They only got 700's, so I assume GM figured OD was a better approach than using gears.
My 90 K5, 3.08's stock with the TBI 350 and 700-R4
Bix's 90 K5, 3.08's stock, with the TBI 350 and SM 465
My buddy's 89 K5, 3.08's stock with the TBI 350 and700R-4
Tire size when ordered seems to come into play as well. The K5's I've seen that got the optional 31 x 10.5's got 3.42 gears. The rigs with the base 235/75's got 3.08's. If you checked off "tow package" I guess 3.73's appeared...but not many K5's got the tow package I don't think.
Bix's 90 K5, 3.08's stock, with the TBI 350 and SM 465
My buddy's 89 K5, 3.08's stock with the TBI 350 and700R-4
Tire size when ordered seems to come into play as well. The K5's I've seen that got the optional 31 x 10.5's got 3.42 gears. The rigs with the base 235/75's got 3.08's. If you checked off "tow package" I guess 3.73's appeared...but not many K5's got the tow package I don't think.
I was "this" close to buying this 84 C10 a while back, it was 305/700R4 with a 2.73 open 10. So far it's the only 2.73 geared truck I've seen, I've seen 2.73's in a handful of G-body's however, usually 6 cylinder cars it seemed.
This little truck would haul, if you looked at the pedal wrong it would break the tires loose, up to around 20 anyway. And that was with a smoky 305 with a Q-jet.
This little truck would haul, if you looked at the pedal wrong it would break the tires loose, up to around 20 anyway. And that was with a smoky 305 with a Q-jet.
Trucks that came with one-off km/h speedometers aren't counted.
Interesting, the '91 brochure here http://brochures.slosh.com/index.shtml?1991 shows 3.08's as well. And no 1/2 ton Suburban. But it's printed in Belgium, in German and English, so I would not be surprised if other non-US destined trucks had the same options.
Even back then the EPA was strongly involved in what the manufacturers would offer, because every gear option offered required another expensive test battery with the EPA to certify emissions. I assume at least Canada in the late 80's early 90's wasn't that bad.
Canada basically waited for the US to test and mandate stuff, then went "looks good, we'll take two".
I'd guess aside from metric gauges, Canadian K5's were identical to the US models throughout the production run.
If you want goofy Canadiana, look to Canadian version of what the big three were selling up until about 1970. Most Pontiacs (except for Firebird and GTO) were Chevy powered, on a Chevy frame, Chevy suspension. Plymouth's here have a ton of Dodge stuff on them, same goes for Mercury. As a Canadian it all looks right to me, but most American's take one look and go WTF???
Anyways, by the early 70's the trade tariff's that created that lunacy were pretty much gone.
I'd guess aside from metric gauges, Canadian K5's were identical to the US models throughout the production run.
If you want goofy Canadiana, look to Canadian version of what the big three were selling up until about 1970. Most Pontiacs (except for Firebird and GTO) were Chevy powered, on a Chevy frame, Chevy suspension. Plymouth's here have a ton of Dodge stuff on them, same goes for Mercury. As a Canadian it all looks right to me, but most American's take one look and go WTF???
Anyways, by the early 70's the trade tariff's that created that lunacy were pretty much gone.
I'd really have to dig back into it, but I recall the late 70's problems with Canadian GM vehicles having Chev engines regardless of the make. IIRC, that is partly what drove GM US to get sued over that exact thing, the vehicles made in Canada being sold down here, and buyers being "duped" into thinking their Pontiac had a Pontiac engine in it, for example.
It's nice to try and rely on the printed literature as "correct", but none of it is really 100% factually accurate, and with the "standard axle" ratio RPO meaning whatever GM meant it to, no way to tell what the "stock" gears were for that vehicle as far as I've ever been able to figure out.
I should pull the diff cover just to make a mess, but I'm pretty sure the '87 K5 in my garage is 3.73. Speculation though that it's original, no way to prove.
It's nice to try and rely on the printed literature as "correct", but none of it is really 100% factually accurate, and with the "standard axle" ratio RPO meaning whatever GM meant it to, no way to tell what the "stock" gears were for that vehicle as far as I've ever been able to figure out.
I should pull the diff cover just to make a mess, but I'm pretty sure the '87 K5 in my garage is 3.73. Speculation though that it's original, no way to prove.
Dorian, that was not a Canadian problem, that was flat out a GM problem and it crossed the border as I recall the very blurry lines when it came to engine brand versus car brand. You can read more here:
http://www.nytimes.com/1977/03/15/a...-swaps-innocent-to-gm-but-sinful-to.html?_r=0
Frankly, the Canadian manufactured Pontiacs, Plymouths, and Mercurys are a quirky but somewhat sought after reaction to tarriff laws of the time. Those tarriffs disappeared in the late 60's, and at the same time so did the Cheviac's, Plodges, etc...
By '77 however GM was using many of the tarriff busting tactics in US production cars as pure cost cutting, which is what got them in trouble.
This was all before my time really, but I want to think there were some Canadian GM model names we didn't see, even if the car itself was the same as whatever we got.
GM somewhat confirms the chev motors in other makes started up your way, at least back to the 60's: https://history.gmheritagecenter.com/wiki/index.php/Canada_Only_General_Motors_Cars I can't recall any US cars that got non-divisional motors before the late 70's. I think all that started then in the US...among others, the 5.7L Olds diesel in trucks, 400 SBC in the Pontiacs, and probably the Buick V6 in everything.
GM somewhat confirms the chev motors in other makes started up your way, at least back to the 60's: https://history.gmheritagecenter.com/wiki/index.php/Canada_Only_General_Motors_Cars I can't recall any US cars that got non-divisional motors before the late 70's. I think all that started then in the US...among others, the 5.7L Olds diesel in trucks, 400 SBC in the Pontiacs, and probably the Buick V6 in everything.
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403 olds in the trans am...
Yes, most of what you're thinking of relates to Canadian Pontiac. Feel free to browse this site for a ton of specific info on them.
http://canadianponcho.activeboard.com/
The lawsuit was shenanigans by GM in the later 70's. The Canadian Pontiac stuff pre-dates that by decades, and was completely legit. What may have happened is some Canadian Pontiacs were re-sold in the US used, and mis-represented.
My personal Canadian Pontiac is a 1957 Pontiac Pathfinder. Canadian only model, built on the same assembly line as the 57 Chevy. In fact, mechanically it is 95% Chevy. same frame, suspension, wheelbase, most interior. It came with a 261 six cylinder, three speed manual. Optional engines were the same iterations of the 283 you could get in the Chevy (right up to the FI 283 hp 283). By way of comparison the US Pontiac of 57 was a Star Chief or similar, longer wider and heavier car, V-8 only (347 cid Pontiac engine). Side by side there is no comparison.
Anyways, we're veering off topic a fair bit. Canadian Chevy's were always identical to the US version, even during the tarriff years. The K5 was never differently built here. All the weird shit over the years was BOP stuff.
Yes, most of what you're thinking of relates to Canadian Pontiac. Feel free to browse this site for a ton of specific info on them.
http://canadianponcho.activeboard.com/
The lawsuit was shenanigans by GM in the later 70's. The Canadian Pontiac stuff pre-dates that by decades, and was completely legit. What may have happened is some Canadian Pontiacs were re-sold in the US used, and mis-represented.
My personal Canadian Pontiac is a 1957 Pontiac Pathfinder. Canadian only model, built on the same assembly line as the 57 Chevy. In fact, mechanically it is 95% Chevy. same frame, suspension, wheelbase, most interior. It came with a 261 six cylinder, three speed manual. Optional engines were the same iterations of the 283 you could get in the Chevy (right up to the FI 283 hp 283). By way of comparison the US Pontiac of 57 was a Star Chief or similar, longer wider and heavier car, V-8 only (347 cid Pontiac engine). Side by side there is no comparison.
Anyways, we're veering off topic a fair bit. Canadian Chevy's were always identical to the US version, even during the tarriff years. The K5 was never differently built here. All the weird shit over the years was BOP stuff.
