Anyone out there have a "heavy half"? 1/2T with 3/4T axles?

[roger0080]

I've seen these around in my lifetime.
Not for a long time now have I seen one.

I came accross some literature about ordering a for example a 3/4T and with some special options you can get the truck rated to haul at the 1T level but you buy the 3/4T model saving you some money (I guess).

I was wondering if that was what the heavy half's I've seen where?

Is there anyone who has one?
Is/was it GMC only that offered that?
Is there an RPO option on the glove box?
How about the VIN number where most GMC's have a dash in it? Is the dash still there?

thanks.
-Roger

[Longhorn Man]

the weavy half was a 73 - 87 thing... none in 67 - 72.

[Stocker]

I didn't think they had 3/4T axles - I thought they were just a 1/2T with heavy-duty suspension and extra cooling. But then again.... I'm not 100% sure!

[71chevylongbed]

the cheyenne super is a heavy half isnt it? that is what i have and the original springs made it ride like a rock

[1969 GMC]

nope, cheyenne and cheyenne super are appearance and trim group options that have nothing to do with payload.

[Longhorn Man]

like i said, there is no heavy half per option package name in the 67 - 72 trucks.
And it was in fact still 5 lug 1/2 ton axles and hubs...just bigger springs.

[roger0080]

I tend to respectfully disagree longhorn man (at this time). Those where like 7.50-16 8 bolt rims and tires (on the rears) that I would see. When looking at the side profile, the rear would be WAY higher than the front like someone purposely jacked it up like a sports car. They weren't 3/4T models either. You'll notice it when you seen them. True 1/2T and 3/4T are more level. Bigger springs in of themselves don't help much; you need the full floating axle with the heavier springs to carry the load. Overloaded 1/2T axles are going to wear out those little wheel bearings real quick.

Let's give the post some time, maybe someone else will share their experiences? Need some old timers to read this. I'm old but not that old!

[lowrider79]

I owned a 1970 Chevy truck that had 16.5 wheels but they called it a 7/8 ton. It was a factory modified 3/4 ton that had the rear end of the truck looking like it was jacked up. It didn't have overloads it was built as a 7/8 ton. I drove that truck everywhere. It would never go faster than 70 MPH but I could pull anything with it and no matter what we put in the box it would not bottom out. It had a 4 speed manual no power steering and no frills. It was originally ordered by Goodyear Tire Company. I believe that it never got better than 11 MPG. I owned it from 1978 to 1983. It was a beast. I know it's not the heavy half that is being refrenced in this post but it shows that these type of modifications did exist. I will go through my old pictures and see if I can find one to scan into this post.

[Jim_PA]

When I ordered wheel bearings for my 72 disc conversion in my 68, they asked if I had heavy duty spindles or not.... this my not apply to what you are talking about, but I found it interesting.

[FormerMember]

Not a 67-72 but I had an 89 "Heavy Half" with the detroit deisel.

Had a 14BSF rear and a 10 bolt front, 6 lug axles.

[3 on the tree]

The 70 Burb that I used to own was rated 500# heavier than a 1/2 ton pickup, yet had the same 6 lug wheels. The front spindles were unique, in that one balljoint was 1/2 ton size and the other was 3/4 ton size. I found this out when a wheel bearing seized and trashed the spindle. Of course, the wheel bearing size was 1/2 ton, so I could not use a 3/4 ton spindle and change the a arm!!!

[Longhorn Man]

Originally Posted by roger0080

Those where like 7.50-16 8 bolt rims and tires (on the rears) that I would see...

These trucks you saw were after production modifcations There is no option code for a full floating axle in the C/10 line up.

Originally Posted by lowrider79

I owned a 1970 Chevy truck that had 16.5 wheels but they called it a 7/8 ton. It was a factory modified 3/4 ton...

You owned this, so I'm not callin BS....but what is the point of modifying a 3/4 ton truck to a 7/8 ton...when a one ton which was already avalible in fleet, step or cab/chassis, was already avalible...and the load rating would only be about 200 pounds less than on the one ton.
Factory modified would fall into the gray area where some would say it is factory...and others would say no...like the crew cabs that chevy never built...but did sell. I would like to see documentation on this if you could please. This sounds interesting. (you aslo describe it with a stump pulling gear...like the 4.56 that is standard in all one tons with the base tranny...a 4 speed.)

Originally Posted by Jim_PA

When I ordered wheel bearings for my 72 disc conversion in my 68, they asked if I had heavy duty spindles or not....

Again, no option code listed in the 67 - 72 books.
The parts stores will also tell you there is no such thing as a 305 v-6 and they'll be offended if you argue the 351 V-6 in a GMC truck. I've won bets with this argument and recieved discounts upon showing proof...my owner's manual.

Originally Posted by grendel

Not a 67-72 but I had an 89 "Heavy Half" with the detroit deisel.
Had a 14BSF rear and a 10 bolt front, 6 lug axles.

Good call. I said they all had 5 lug.... I stand corrected.
The 2 wheel drive heavy half trucks had 5 lug wheels. The 4X4 ones had 6 lug.

Originally Posted by 3 on the tree

The 70 Burb that I used to own was rated 500# heavier than a 1/2 ton pickup, yet had the same 6 lug wheels. The front spindles were unique, in that one balljoint was 1/2 ton size and the other was 3/4 ton size.

The GVW can be tricky. and I have not figured the rhyme or reason for some of the GVW tricks. Why is my one ton rated at 9000 pounds, when another one I looked at that was also a single rear wheel, 350/th400....just like mine was originall...was rated for 10k?
As for your funny ball joint issue. Some one before you probably hogged out the hole with a sloppy junk pall joint and did this mod as a cheap fix...machining the arm and the spindle could be ceaier than tracking down parts in the mid 80's when parts stores and the dealewr were handling less parts for them, and the restoration market was nill. Ppl will do anything to keep a truck on the road.

I understand GM did funny things, one off this, and no reasonable explination for that... but there is no documentation of the heavy half untill 82 or so IIRC. This was hashed out 3 or so years ago and a 73 - 87 guru stepped in and explained the heavy half marketing. I just wish I remember what the angle was.

[da-burb]

The 70 Burb that I used to own was rated 500# heavier than a 1/2 ton pickup, yet had the same 6 lug wheels. The front spindles were unique, in that one balljoint was 1/2 ton size and the other was 3/4 ton size. I found this out when a wheel bearing seized and trashed the spindle. Of course, the wheel bearing size was 1/2 ton, so I could not use a 3/4 ton spindle and change the a arm!!!

I'd bet that your burb came with 3 rows of seats. I've read that 9 passenger burbs had 3/4 ton parts in the front end. 6 passenger burbs had normal 1/2 ton parts.

[jc]

the 1972 cheyenne10 super 4x4 i sold a few weeks ago was titled as a half ton
and all numbers matched. this truck had a 3/4 ton axle setup that look original and untuched. the person i baught it from in jersey baught it in texas and was told it was baught new like that. i can not prove this as i am not the original owner but i suspect things like this were done to avoid the regastration fees of a 3/4 ton. possibly dealer upgrade is what i lean to

[Robert1970C20rstbukt]

One of my friends has a '79 K10 heavy half and it has 6 lug axles, front and rear. I saw a K10 Burb here in town that has 5 lug axles, so yeah the heavy half thing was just for 70s and 80s trucks.

[Longhorn Man]

whats the vin on that?

[3 on the tree]

Originally Posted by da-burb

I'd bet that your burb came with 3 rows of seats. I've read that 9 passenger burbs had 3/4 ton parts in the front end. 6 passenger burbs had normal 1/2 ton parts.

You are correct. It also came with the rear ac unit. I bought this rig from the orig owner, and it never had any front end work done to it. The front spindle described was OE, and one NAPA store even had it listed in a parts book, but no longer available. BTW, it had a 4 bolt main 350 in it, and the Turbo 350 tranny pan had a factory drain plug.

[jc]

Originally Posted by Longhorn Man

whats the vin on that?

is this directed to me?
if so ill see if i can find it.

[1969 GMC]

Originally Posted by Robert1970C20rstbukt

One of my friends has a '79 K10 heavy half and it has 6 lug axles, front and rear. I saw a K10 Burb here in town that has 5 lug axles, so yeah the heavy half thing was just for 70s and 80s trucks.

All Chevy 1/2 ton 4x4's (except new stuff, not sure on that) have 6 lug wheels. No 5 or 8.

[69 Short Fleet]

Lowrider was your 1970 a possible COPO? (being a Goodyear Tire Co. truck) Do you remember any additional documentation on it when you bought it? Just curious. Doug

[Longhorn Man]

Originally Posted by jc

is this directed to me?
if so ill see if i can find it.

I'm sorry...yeah you JC.

[dwaite72lnghrn]

I always thought the "heavy half" started around '75 to get around the emissions that were going into effect on pickups under a certain GVW the heavy half option raised the gvw up about 500 lbs to keep cats off the truck. Not sure what options gave it the increased GVW but that is what I recall from that time.

[lowrider79]

Originally Posted by 69 Short Fleet

Lowrider was your 1970 a possible COPO? (being a Goodyear Tire Co. truck) Do you remember any additional documentation on it when you bought it? Just curious. Doug

I don't know. I may have the vin number somewhere but it will take a lot of digging. If I have extra time I'll look. It may take a month or so since it's still summer I have things to do.

[Burbinite]

My '72 GMC suburban 4x4 has 3/4 springs in the rear. 1/2 ton everything else. I don't know if it's original but it sure looks it. (same patina as frame)

[special-K]

GM offered suspension options:HD springs,HD shocks,leaf spring(heavier duty than coils by design),and helpers for coils.It didn`t change the designation on the model.There was no "Heavy Half" as a model until the late 70s,like`78 I think.These were a marketing move and were nothing new that you couldn`t get in 67-72,except the name(sticker on rear quarter).In the`88-ups there are heavy-optioned 1500s with the 14-bolt semi-floating rear w/6-lug outers,standard with diesel option.The 2500s all have the same axle unless equipped with the SP23 (HD suspension option)that included 8-lug hubs front & rear.The rear was the 14-bolt full-floating axle with 1" larger diameter ring gear.LonghornMan is correct.There`s your answer.