Axle Swap Heavy Half - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Foot Stomper · 05-12-2022, 11:15 PM

So my dad swapped out the rear axle in the family 59 with a 1980ish Heavy Half rear axle to get a higher gear ratio.
It fit very well and he swapped out the 5 bolt axles with 4x4 6 bolt axles to keep the original 6 bolt rims. (It's only about an 1 1/2" wider than the original.)
Can anyone tell me what the 6 bolt axles would be from?
I need a speedy sleeve and want to get the right one.

**kwmech** · 05-13-2022, 12:21 AM

How many bolts on the rear diff cover?

Foot Stomper · 05-13-2022, 11:00 AM

Quote:

Originally Posted by kwmech

how many bolts on the rear diff cover?

12

**kwmech** · 05-13-2022, 11:09 AM

I don't think there any variations in size with the 12b axle-----not like the later model 10b or 14b. Try an application like a 75 K10. OR you can pull the rear diff cover and get a date off of the ring gear

SCOTI · 05-13-2022, 11:15 AM

Anything 73-80 truck or Blazer 4x4 would be my starting reference point for a parts search.

LT7A · 05-14-2022, 09:52 AM

That family 59 is a neat truck!

05-12-2022, 11:15 PM	#1
Foot Stomper Registered User Join Date: Oct 2015 Location: Calgary, Alberta Posts: 1,252	Axle Swap Heavy Half So my dad swapped out the rear axle in the family 59 with a 1980ish Heavy Half rear axle to get a higher gear ratio. It fit very well and he swapped out the 5 bolt axles with 4x4 6 bolt axles to keep the original 6 bolt rims. (It's only about an 1 1/2" wider than the original.) Can anyone tell me what the 6 bolt axles would be from? I need a speedy sleeve and want to get the right one. Attached Images __________________ So when is this "Old enough to know better" supposed to kick in? My 1959 GMC build thread http://67-72chevytrucks.com/vboard/s...d.php?t=686989

05-13-2022, 12:21 AM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,395	Re: Axle Swap Heavy Half How many bolts on the rear diff cover?

05-13-2022, 11:09 AM	#4
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,395	Re: Axle Swap Heavy Half I don't think there any variations in size with the 12b axle-----not like the later model 10b or 14b. Try an application like a 75 K10. OR you can pull the rear diff cover and get a date off of the ring gear

05-13-2022, 11:15 AM	#5
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 21,914	Re: Axle Swap Heavy Half Anything 73-80 truck or Blazer 4x4 would be my starting reference point for a parts search. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

05-14-2022, 09:52 AM	#6
LT7A Registered User Join Date: Oct 2015 Location: PNW Posts: 3,513	Re: Axle Swap Heavy Half That family 59 is a neat truck!



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