Heavy half question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dann · 02-16-2020, 12:50 AM

I got a 1971 custom gmc half ton w a 402 with the 400 tranny . 5lug w rocker springers . Had to replace a stud a regular half ton stud was to small I got a 3/4 ton stud It fit, I was told my truck is a heavy half 3/4ton rating . Gm 12bolt rear main trying to find out if and how i can tell if its a heavy half
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**davischevy** · 02-16-2020, 01:11 AM

All 71, 72 1/2 ton GM trucks had 1/2" x 20 studs.

**davischevy** · 02-16-2020, 01:13 AM

Options are listed on the SPID in the glovebox.

**special-K** · 02-16-2020, 08:51 AM

The "Heavy Half" thing came about in the later '70s. Sounds like it was a parts person who doesn't have accurate information. A big block truck will have a slightly higher GVW stamped on the Vin-plate due to heavier engine. Does your truck have a 12-bolt rear or a Dana?

What size stud did you end up using? 3/4t trucks used 9/16" studs and all were 8-lug full-floating rear with a "2" for the third digit in the VIN. The blending of 1/2 and 3/4t had not come about yet.

**Steeveedee** · 02-17-2020, 11:13 PM

Quote:

Originally Posted by special-K

The "Heavy Half" thing came about in the later '70s. Sounds like it was a parts person who doesn't have accurate information. A big block truck will have a slightly higher GVW stamped on the Vin-plate due to heavier engine. Does your truck have a 12-bolt rear or a Dana?

What size stud did you end up using? 3/4t trucks used 9/16" studs and all were 8-lug full-floating rear with a "2" for the third digit in the VIN. The blending of 1/2 and 3/4t had not come about yet.

Yup, parts man follies. I found this 9/16" stud business out when I put the front disc brake kit on my truck and had to go buy 16 each 9/16" nuts...and another socket for the tool kit in the truck. Little things that bite.

02-16-2020, 12:50 AM	#1
dann Registered User Join Date: Dec 2014 Location: Sheridan,wyoming Posts: 3	Heavy half question I got a 1971 custom gmc half ton w a 402 with the 400 tranny . 5lug w rocker springers . Had to replace a stud a regular half ton stud was to small I got a 3/4 ton stud It fit, I was told my truck is a heavy half 3/4ton rating . Gm 12bolt rear main trying to find out if and how i can tell if its a heavy half Posted via Mobile Device

02-16-2020, 01:11 AM	#2
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,836	Re: Heavy half question All 71, 72 1/2 ton GM trucks had 1/2" x 20 studs. __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

02-16-2020, 01:13 AM	#3
davischevy Senior Member Join Date: Sep 2008 Location: Harrison, Arkansas Posts: 9,836	Re: Heavy half question Options are listed on the SPID in the glovebox. __________________ other Larry Build thread, Arkansas K10 https://67-72chevytrucks.com/vboard/...=755797&page=5 The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.

02-16-2020, 08:51 AM	#4
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: Heavy half question The "Heavy Half" thing came about in the later '70s. Sounds like it was a parts person who doesn't have accurate information. A big block truck will have a slightly higher GVW stamped on the Vin-plate due to heavier engine. Does your truck have a 12-bolt rear or a Dana? What size stud did you end up using? 3/4t trucks used 9/16" studs and all were 8-lug full-floating rear with a "2" for the third digit in the VIN. The blending of 1/2 and 3/4t had not come about yet. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~



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