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Old 02-16-2018, 09:57 PM   #1
'68OrangeSunshine
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3.08 Ratios in a K/10 Sub

Would 3.08 ratios in a 12 bolt posi rear and D44 front work out in a '67 K/10 Suburban with a 292 L6 plant?
Currently Sub is set up w/ 3.73 12 bolt rear [which blew up] and a closed knuckle GM front diff w/ drum brakes. It has a 454 V8 [needs rebuild] and a TH350/NP 205 [also should be overhauled]. When gas was under $1.50/gal it was viable, but 6 City- 8 Hwy doesn't work for me. BBCs are fun but spendy.
I have a couple of 292 cores, and I know some tricks to wake an L6 up. I also have a SM465/T-221 core. Thinking also of a 700-R4. [Don't have it]. I have a core 3.08 12 bolt rear on a '72 K/S spare tub/frame.
Changing out the front diff to a D44 would give me power steering and power brake options. 1967 MY used ram-assisted power from the factory, and since Corvettes also used that system for P/S, parts are only touchable if you have a NASA-style budget.
Braking with the MY '67-'68-Only front brake drum was on the order of Fred Flintstone dragging his feet on the rubble. [Also it's a hard-to-get drum.] Sometimes when panic stopping, my best option was to select a softer target. Thus the desire for discs in front.
I can get a milsurp new-on-the-pallette D44 for '73-'87 CUCV Blazer, 6-bolt lugs, for $500 and $280 shipping. That's cheaper than rebuilding what I have. Only glitch is it's only available in 3.08. I hear the front D44 is the same as a '69-'72.
My '67 Suburban ''White Fang'' has been sitting since 1998. I'd like to get it going again. Still a pipe dream now.
Comments welcome.
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Old 02-16-2018, 10:27 PM   #2
Bigdav160
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Re: 3.08 Ratios in a K/10 Sub

Only a couple comments. Someone in the truck section was looking for pictures of 67-68 power steering equipped K trucks. I assumed it wasn't available as I didn't see it listed in the option list. A lot of people agreed but someone posted this pic:



If the ram and control valve parts are the same as Corvette there are repair parts readily available and the seal kits are cheap. less than $20 for both kits. Rebuilt power cylinders and control valves probably only cost a couple hundred.

Manual trans and a 3.08 isn't a good combination. You'll be using a lot of clutch to get it moving.
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Old Yesterday, 12:14 AM   #3
Average Joe
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Re: 3.08 Ratios in a K/10 Sub

Why not run the BB with the 3.08's?

I picked up 1 mpg in town and almost 3 mpg on the highway when i swapped from 3.73's to 3.07's in my C10 'Burb.
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Old Yesterday, 12:55 AM   #4
mongocanfly
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Re: 3.08 Ratios in a K/10 Sub

before you decide on a gear swap you need to do the math on rpm/gear ratio/trans gear/tire size....heres a calculator to help.....
http://www.csgnetwork.com/multirpmcalc.html
jumping to a od trans [700r4] from a non od trans [sm465,th350] makes a big difference in rpms
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Old Yesterday, 01:19 AM   #5
'68OrangeSunshine
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Re: 3.08 Ratios in a K/10 Sub

Quote:
Originally Posted by Average Joe View Post
Why not run the BB with the 3.08's?

I picked up 1 mpg in town and almost 3 mpg on the highway when i swapped from 3.73's to 3.07's in my C10 'Burb.
Because I'd have to rebuild the 454 anyway, and I didn't like the mileage.
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