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1977 C10 or C20?

  
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1977 C10 or C20?

 
KyBorn231 KyBorn231
New User | Posts: 7 | Joined: 06/12
Posted: 06/12/12
08:14 AM

Hello. I just joined the forum, and I am trying to make a determination about a truck that my husband had in order to sell it. He passed away in 2009 and was a supreme gearhead from the old school. He grew up with muscle cars and loved them all. He built drag cars, raced, and was a toolmaker...you get the picture. I need to thin out some of his collection.

He had kept a 1977 Chevy truck that he always called the "3/4 ton." He always said that it was an unsually solid truck because 1977 trucks were notorious for rust. I have spent a number of hours trying to research 1977 trucks and the differences between the C10 and C20. The reason for this is that, according to the VIN on the door post, the truck is a C10. (The fourth digit is a 1.) GAWR is 2940 front and rear. The VIN is put on with rosette rivits, so am I right to assume this is the original VIN plate?

But,the badges say C20. While I realize that someone could've just swapped badges, my trash truck is a 1977 C10 to compare it to, and the "C20" just seems heavier.

The pumpkin part of the rear end has this on it on the front side:
7
CF D
164
8977328

on it.  I haven't been able to find out what this means.

I also found a parts number at the bottom of the steering column
7802644
10   34

I can look for other numbers if I know where to look.

It has leaf springs. The C20 has 10 leaves in the rear springs while the C10 I have has only 8.  Could this truck be a heavy-duty package C10?

The VIN also says,

Camper Loading CG Data
CWR  5560 IM  A  74  IN Dim 8  0 IN

Does this mean the max. weight of a slide-in is 5560 lbs.? What does the rest mean?

I haven't had the hubcap off in the rear to count the lugs. I understand that C20 are 8 lug and C10 are 5 or 6?

If I'm reading the VIN plate right, the truck should have 15" tires. It has 16. The tires on it now are LT 235/85R16 M+S

This truck has been garaged kept for the last 12 years. My husband had owned it since 91. He had a design in his head for a carburetor that would make it get better gas mileage and was keeping it for his retirement years. But, he never got to do that.

The interior looks original. The dash is not cracked. It's not missing any trim that I can see.  I think it has a 350 V-8. (Nothing but V-8's were allowed around here!)It's a cold-natured start.

I know it is good truck, but I don't want to misrepresent what it is.  This is part of our child's inheritance, so I'm willing to go to some effort here. I had it officially appraised, and there was no problem with the VIN. I had not looked up the VIN then. It was called a C20 in the appraisal and they used their computer to look up VINs, so I'm a little confused. I'm in the process of trying to look up the previous owner to ask him about the truck. Maybe I'll get lucky.

What I would like from the forum folks is any help in identifying it as a C10, C20, or some combination of the two.

I am probably not going to be able to take anything apart, so I will have to have info that I can visually check. I haven't been able to see an engine number, but I'm not sure I'm looking in the right place. I know that the motor may not be original, but the VIN says it should be a 350 V-8.

This truck is very solid with virtually no rust. Paint is very good, and it is a Scottsdale. The bed has had some sealant around the seams, so rust is not a problem. This truck looks very good as is.  I would like to sell it to someone who loves old trucks and would like to keep it on the original side.  

Sorry for the long post. Thanks for any information or advice you can give me.  

KyBorn231 KyBorn231
New User | Posts: 7 | Joined: 06/12
Posted: 06/13/12
08:03 PM

Well, I found out that I'm counting the leaves wrong. The C20 has 8 leaves and the C10 has 6.  Also, the paperwork on the C20 shows my husband as the second owner. I have the papers the first owner got when the car was inspected. It lists the original numbers. Haven't gotten into those yet.  

motorman96 motorman96
New User | Posts: 4 | Joined: 06/12
Posted: 06/16/12
04:31 PM

Hello there. I recieved your post yesterday, but it took me this long to get my leaves counted.  I have a 1977 c20...."Camper Special".  Beautiful Truck.  Has a 454ci motor in it, with 2-wheel drive, 4:10 posi rearend.   Now.....my leaf springs in back have 10 leaves with one big over-load leaf at the bottom.  They list my truck as a 3/4 ton at the DMV, but I suspect it might be a 1 ton. (Camper Special) You say a c20 has 8 leaves on the spring, its prob a 3/4 ton. I would say.             Mine rides REALLY tight. 16.5" tires. Which were hard to find, but I wanted to keep the chrome rims.  I will keep looking and if I find anything that helps answer this question, Ill send it to you.  Sounds like youve got a cream puff there. I love my truck, I just wish it got better gas mileage. Im gettin about 12 around town. But...she is VERY fast. Sharp ride that turns heads everywhere I take her.  

motorman96 motorman96
New User | Posts: 4 | Joined: 06/12
Posted: 06/16/12
05:02 PM

My tag inside the drivers door has these listings; GVWR 8200.....GAWR front 3800.....GAWR rear 5560.   9.50-16.5 tires.  

KyBorn231 KyBorn231
New User | Posts: 7 | Joined: 06/12
Posted: 06/17/12
01:33 PM

Your truck sounds really nice! Lots of power. The tag on my truck has GVWR 5300. Where does yours say it's a camper special? I've read that many 1960s and 1970s trucks were set up to appeal to campers.

I don't know the gear ratio, and I would rather not have to get into teeth counting. Do you think the numbers in my first post could reveal any information on the gear ratio? Maybe it's like a 3.73, but I don't know--the gas mileage is not so good if I remember. I haven't found any websites that explain the numbers on the pumpkin, but I haven't given up yet.

Thanks for your help.
KyBorn231  

waynep71222 waynep71222
User | Posts: 221 | Joined: 05/12
Posted: 06/17/12
10:10 PM

73 78Vin

do you still have your label with all the 3 letter codes across the bottom...

AO1 - Softray Tinted Glass

AO1 - Tinted Glass All Windows

A28 - Sliding Rear Window

A31 - Power Windows

A80 - Pick Up Box Bed Rails

AN1 - Folding Seat Back

AU3 - Power Door Locks

B32 - Color Keyed Front Floor Mats

B3J -Diesel Equipment

B84 - Black Body Side Moldings (Fleetside Only)

B85 - Bright Body Side Moldings (Fleetside Only)

B93 - Door Edge Guards

B96 - Wheel Opening Moldings

C42 - Heavy Duty Front Heater (Not Available with RPO C60 A/C)

C60 - Air Conditioning

C91 - Dome Lamp

C1A -Blazer with white convertible soft top

C1B - Blazer with black convertible soft top

C1C - Blazer with blue convertible soft top

C1D - Blazer with buckskin convertible top

CD4 - Intermittent Windshield Wiper System

D44 - Painted Below Eyeline Mirrors

D45 - Stainless Steel Below Eyeline Mirrors

D73 - Pickup Box Side Rails

DF2 - Camper Style Stainless Steel Mirrors

DG4 - Extended Below Eyeline Mirrors

DG5 - Senior West Coast Style Painted Mirrors

E62 - Stepside Pick Up Box

E63 - Fleetside Pickup Box

E81 - Wood Floor Fleetside Pickup Box

F44 - Big 10 Model

F51 - Heavy Duty Shock Absorbers

F60 - Heavy Duty Front Springs (Came With HD Front & Rear Shocks Recommended For Snow Plow Use On 1/2 Ton Trucks)

G50 - Rear Heavy Duty Springs

G51 - Rear Extra Capacity Springs

G60 - Rear Main And Auxiliary Springs (30 model series only)

G80 - Locking Rear Differential

GT4 - 3.73 Rear Axle Gear Ratio

GT5 - 4.10 Rear Axle Gear Ratio

HC2 - 2.76 Rear Axle Gear Ratio

HC4 - 4.56 Rear Axle Gear Ratio

HC8 - 3.21 Rear Axle Gear Ratio

HE3 - 3.07 Rear Axle Gear Ratio

HO4 - 4.11 Rear Axle Gear Ratio

J55 - Heavy Duty Power Brakes

K22 - 94 Amp Alternator

K30 - Speed & Cruise Control

K34 - Electronic Speed Control

K43 - Poly Wrap Air Cleaner

K81 - Cold Climate Package (Including Special Insulation, 66 Amp Alternator, Special Heater & Defroster, Engine Block Heater, HD Battery.)

KC4 - Engine Oil Cooler

KO5 - 600 Watt Engine Block Heater

LE8 - 7.4 Liter V 8

LE9 - 5.0 Liter V 8

LF3 - 5.0 Liter V 8

LF4 - 400 4bbl V 8 Engine

LG9 - 305 2bbl V 8 Engine

LO5 - 5.7 Liter V 8

LS9 - 350 4bbl V 8 Engine

M15 - 3 Speed Manual Transmission

M20 - 4 Speed Manual Transmission (Chevrolet CH465)

M40 - Turbo Hydra-matic Transmission

MX0 - TH 700 Transmission

MX1 - TH 350 Transmission

N31 - Custom 16" Steering Wheel

N33 - Comfortilt Steering Wheel

N41 - NP 203 Fulltime 4wd Transfer Case

N67 - Rally Wheels (1/2 Ton Trucks Only)

N90 - Aluminum Cast Wheels

NK7 - 31 gallon Fuel Tank

NL2 - Auxiliary Fuel Tank (pick ups)

NY1 - Fuel Tank Shield

NY7 - Transfer Case Shield (Skid Plate)

P11 - Glide Out Spare Tire Carrier

P13 - Side Mounted Spare Tire Carrier (Fleetside Only)

PO1 - Bright Wheel Covers (1/2 Ton Trucks)

PA1 - Bright Metal Wheel Covers (3/4 Ton Trucks)

RO5 - Dual Rear Wheels ( 1-Ton Trucks Only)

TP2 - 3500 Watt Aux. Delco

TT5 - Halogen High Beam Headlamps

U01 - Roof Marker Lamps

U16 - Tachometer

U35 - Quartz Electric Clock

U37 - Cigarette Lighter

U58 - AM/FM Stereo Radio

U63 - AM Radio

U69 - AM/FM Pushbutton Radio

U69 - AM/FM Radio

U76 - Windshield Antenna

UA1 - Heavy Duty Battery

UF2 - Cargo Lamp

UM6 - AM/FM Stereo Radio With Seek, Scan, Stereo Cassette Player & Clock

UN3 - AM/FM Stereo Radio With Stereo Cassette Player

UY7 - Trailer Light Wiring Harness

VO1 - Heavy Duty Radiator

VO2 - Transmission Oil Cooler

V22 - Chrome grille

V31 - Chrome Front Bumper Guards

V42 - Chromed Rear Step Bumper (Fleetside Only)

V43 - Painted Rear Step Bumper

V76 - 2 Front Tow Hooks

VF1 - Chromed Rear Bumper

VR2 - Dead Weight Trailer Hitch

VR4 - Weight Distributing Trailer Hitch

X6Z - Automatic Front Locking Hubs

YE9 - Silverado Trim Package

YG1 - Custom Package (Fleetside Only) Including Bright Wheel Opening Moldings, RPO #'s B84, B96, & Bright Trim For Side Marker Lamps & Tail Lights.

YG3 - Deluxe Package Including Bright Trim For Side Marker Lamps & Tail Lights.

YG4 - Means rear seat not desired (Bonus Cab, Crew Cab, Blazer, Suburban).

YJ6 - Decor Value Package

YWF - 10 x 16.5/ Load Rating "D" Tubeless Tires

Z53 - Gauge Package (Including Voltmeter, Engine Coolant Temp, 66 Amp Alternator)

Z56 - Cold Climate Package

Z58 - Blazer white hard top

Z59 - Blazer black hard top

Z62 - Scottsdale Trim Package

Z84 - Cheyenne Trim Package

Z75 - Front Quad Shock Absorbers (Dual Shocks)

Z81 - Camper Special Chassis Equipment

Z82 - Trailering Special Package

Z84 - Cheyenne Trim Package

ZQ2 - Operating Convenience Package Including AU3 Power Door Locks & A31 Power Windows

ZY1 - Solid Paint

ZY4 - Deluxe 2-Tone Paint

ZY5 - Exterior Decor Package  

KyBorn231 KyBorn231
New User | Posts: 7 | Joined: 06/12
Posted: 06/18/12
07:34 AM

Thanks, WayNep, for your help. I appreciate it. I'm going to print the codes and see which I can identify. I still have questions though. (See first post.) The fourth digit is for a 1/2 ton and the truck is called a C-20. So, I'm thinking it has some heavy-duty options maybe. The leaf springs are heavier than those in my 1977 Silverado. The tires are 235/85R16 and the Silverado has 15 in. I know there's some leeway on tire sizes, but my husband always called it "the 3/4/ ton."

I have some more information from the original papers: Engine # V0411-TKB,  Transmission Y7C-22D, and Axle KAX 108W72 From the VIN, the motor should be a 350 V-8 4BBL. The truck has automatic transmission, but I haven't tried yet to go any deeper on these numbers.  Thanks for any and all help.  

KyBorn231 KyBorn231
New User | Posts: 7 | Joined: 06/12
Posted: 06/18/12
07:38 AM

Also, to all, does anybody have any specifics on these codes?  Z81, Z82, VR2, or VR4?  Thanks.  

KyBorn231 KyBorn231
New User | Posts: 7 | Joined: 06/12
Posted: 06/18/12
12:43 PM

OK, according to this website    http://www.maliburacing.com/auto_tranny_id.htm (which was really helpful), my transmission is a TH350.  The shape matches and the pan has 13 bolts. Says this Xms is for usage: low torque, heavy car.  

waynep71222 waynep71222
User | Posts: 221 | Joined: 05/12
Posted: 06/18/12
09:28 PM

camper specials usually have holes drilled into the sides of the truck bed for brackets to hold the slip in camper in place with turn buckles..   there may also on the 77 models braces on the windshield pillars for the front shocks to dampen the motions to the overhead camper section..

my brother in law had a 73 C20 4x4.. and replaced it with a special order C30  camper special with a 2 door cab..  the massive dolphin camper he had ordered bowed the axle under the C20..  had to wait 10 months for the special order C30..  the C30 came with the 454.. he swapped on headers.. rejetted the carb..  but made a HUGE mistake.. he adjusted the APT screw.. i was there.. watched him get in there with a pair of needle nose..  he was never happy again..  


Apttool

VR2 and VR4 are slightly different styles of REAR BUMPERS or the hitches below them..


i managed to get a cheep 78 C20.. the truck i always wanted..   my nephew begged me out of it.. all it needed was a replacement drivers door..  as it had been folded back when it was hit. did not even bend the jam..  i measured..  i just had not found the proper color in the wrecking yard..  he ripped the 454 out and sold it.. scrapped the truck.   since it previously had a huge camper on it.. it only had 55K miles.. what a waste..  

waynep71222 waynep71222
User | Posts: 221 | Joined: 05/12
Posted: 06/18/12
09:37 PM

there are NO instructions for resetting the APT adjustment .. and the tool shown above will NOT work when the carb is assembled...  but a proper adjustment is needed if you have swapped anything that will effect air fuel ratio..


the APT adjustment limits the downward movement of the primary metering rod hanger..

since a quadrajet gets onto the main circuits at a MUCH lower RPM.. this adjustment is critical..

if the APT is too low.. the carb will backfire on acceleration.. and have a horrific flat spot just off idle..  it will also be hard to drive at low RPMs..

if the APT is too high.. the air fuel ratio will be way rich and fuel economy will be in the dumpster..

if you have NOT adjusted the APT screw .. DON'T..  if the carb has been rebuilt.. you might end up doing it..

the proper way is with a carb expert on a chassis dyno and a smog machine up the tail pipe..  at PART Throttle ..

or..

with seat of the pants tuning 1/4 turn at a time over several days between adjustments..

cheep air fuel ratio gauges can also be used..

most dyno tuners want to tune for full throttle power..   not part throttle drivability and fuel economy..  

KyBorn231 KyBorn231
New User | Posts: 7 | Joined: 06/12
Posted: 10/11/12
06:14 AM

WayneNep, I have had life intervene and haven't been on here for a long time, so I'm sorry I haven't responded until now. I will look for the bed holes.  I'm not sure about what I'm looking for with the brackets near the window posts. What's the best way to view this?

Your story about your nephew was unfortunately not an uncommon story.  Young people often just want a fun drive--chop, part, and paint.  They get a kick out of making something "unique" but not out of having something original. They probably don't or can't have any actual memories of seeing the vehicle new as do older drivers. Of course, there are some that love the originals, too.

As far as the carb advice, thanks. I'm NOT touching it and won't let anyone else.  The truck is cold-natured but doesn't have any problems starting when the temps are up.

It's a weekend truck, not a daily driver.  Would like to sell it to someone who would appreciate it and take care of it. I took a bunch of photos of it that I could email to anyone seriously interested.  

motorman96 motorman96
New User | Posts: 4 | Joined: 06/12
Posted: 10/08/13
05:58 PM

The previous owners son had the truck painted, and the Camper Special metal insignia came with it, in the glove box.  It looked better w/o them, so I left them off.  Not sure about the rearend numbers. Never looked into them. The manufactures option list was with the truck. Thats where I got the rearend ratio from.   Ive found so much about my truck on the internet, you might find something there. Good luck friend.  

nize66 nize66
New User | Posts: 5 | Joined: 09/13
Posted: 10/12/13
12:35 PM

if it has 8 lug wheels its a c20 3/4 ton  

motorman96 motorman96
New User | Posts: 4 | Joined: 06/12
Posted: 12/20/13
08:39 AM

the previous owner had it painted, and the "Camper Special" metal insignia plates, that were just behind the cab, were in the glove box. Also has the metal brackets sticking out from the front of the bed to tie the camper to. Has clip-on brackets sticking out of the rear bumper on either side also for attaching the camper. Has the sliding rear window that opens to the camper when its on too. I wish I could figure out how to put a pic of it out here, but apparently Im not that smart. Smile Anyways, hope this helps.   ps; I finally got a radar detector for it......after 3 tickets for speed, it does help!  This truck will go 80 mph without you even realizing it!  

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