what other years rear end fit my 1979 chevy c-10 big ten.

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BrianCarroll

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5.3 LS swap
I have A chev sport truck 1979 short bed newer LS motor
with fitech injection Muncie M-21 and a 3.73 rear end . 10 bolt one wheel drive.
My question is square bodt 79-80 are all the rear ends inter changable ?

I would like a posi
Also would like to hear which ratio would reduce my rpms .
 

Ricko1966

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Any ratio less than 3.73 will reduce your rpms. You should actually go online and find a rear gear calculator so you can see the differences tires and gears make. As for rearends if you are insistent on changing whole rearends,I can't tell you what all years bolt right in,and what mods need to happen. When you say bolt right in,do you mean no mods at all to make it work? Now I can tell you an 8.5 GM differential and gear set is an 8.5 differential and gear set. So if your shopping for a certain gear ratio and a posi diff in the bone yards its going to be lots easier to find what you are looking for if you just go with the intention of buying the ring,pinion and differential out of any 8.5 10 bolt that has the right gears and posi. Whether it's in a Truck,an Impala,a Skylark,a Firebird etc. Thousands of 10 bolts to choose from.VS a few certain trucks.
 

77Dmax

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The m21 will limit your options. You might look into an m20 or even better an m23z from autogear.
 

77Dmax

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M21s have a 2.20:1 first gear ratio. Math it out.
 

BrianCarroll

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5.3 LS swap
why you ask I am constantly burning up one rear tire ,the LS has lots of power and no weight in the rear makes it easy to smoke the tire plus like I said in my second post i think a posi would give me even wear.
Also i suspect there is lots of wear in my existing rear end beyond the worn out diff the c clips appear to be worn badly.
 

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