main differences between 73-79, 81-87

[Keith Seymore]

Originally Posted by GonicGM

R/V designations started in 1987 for all square body
Never known through confirmed VIN or ownership...There were square body SRW std. cab pickups available for 1988 model year. The GM parts book confirms as there is a listing for frame rails as 1988 V309(03), would have been available with carb. or FI.

I can confirm that the R/V designation started in 1987, both by ownership and by professional experience.

K

[UKNOWME]

Originally Posted by Keith Seymore

I can confirm that the R/V designation started in 1987, both by ownership and by professional experience.

K

What's the difference in C/K vs R/V?

[bhc41051]

Originally Posted by Captkaos

You both would be correct on the gas door. It "officially" started on '79 for the pickups, but it started in '78 on the blazer/burbs. As for Cats, I had a '75 that had them. Cats were determined mainly by the GVWR of the Truck.

In 1975 catalytic converters were standard on all pickups under 6,001 lbs. GVW

[Keith Seymore]

Originally Posted by UKNOWME

What's the difference in C/K vs R/V?

They are the same (except for the model year and TBI).

The designation was changed to avoid confusion with the new GMT400 models, which retained the C/K codes.

K

[UKNOWME]

Originally Posted by Keith Seymore

They are the same (except for the model year and TBI).

The designation was changed to avoid confusion with the new GMT400 models, which retained the c/k codes.

K

Thanks

[naussme13]

i was wondering if the grill from a 85 will fit my 81 i can't find it anywhere else and just want to be sure before i buy one

[TKCR]

Originally Posted by naussme13

i was wondering if the grill from a 85 will fit my 81 i can't find it anywhere else and just want to be sure before i buy one

Here's a thread that should answer that question

http://67-72chevytrucks.com/vboard/s...+swap+85+to+81

[rich weyand]

1975 was first year for cats in C-10. 1979 was first year for cats in C-20/30, K-10/20/30.

1978 was first year for electric oil pressure gauge instead of pressure-tube gauge.

1979 was the first year for gas filler doors.

[rich weyand]

Originally Posted by boataddict26

I am wondering if the bed from an 86 will fit onto my 78. Will it?
Thanks,
Mike

Yes, the bed from an 86 will fit on a 78. That's exactly what I have.

Bear in mind that the fuel filler necks are different. Different angle, different diameter, different length. I replaced the filler necks, the filler neck hoses, and the gas tanks (the filler neck hose nipple is bigger, to address slow-fueling issue) on my dual-tank setup to get it all right. You can find the filler necks on car-part.com, which is the salvage yard search site. Hoses and tanks from LMC, etc.

[GonicGM]

[QUOTE=rich weyand;7869855]1975 was first year for cats in C-10. 1979 was first year for cats in C-20/30, K-10/20/30.QUOTE]

Catalytic converters were required by GVW. For instance, in 1977, the GVW break would have been about 6000 GVW. Our 1977 4x4 Jimmy, owned since 1979, was 6200 GVW, had original exhaust and no cat, no EGR. My 77 C1500 was 5300 GVW and had a cat.

Catalytic converters were not installed on one tons until 87 and had to be fuel injected, at least in non-California domestic. Same goes for 3/4 ton. The break at that point was 8500 GVW. Under would have a Cat. over did not, unless fuel injected. In fact, through 1989, you could still opt for a carbureted one ton with stainless steel dual exhaust, leaded gas spec. They still had the large hole filler necks like the diesel. I can confirm this on both my 83 and 85 K30.

[77GMCSerria]

I have a 1975 Chevy truck with some cab damage(they don’t make repair panels for this location), I was wondering if I could use a 1986 cab for parts. The damage is behind the door on the passenger side of the cab.

[93M6Formula]

Originally Posted by 77GMCSerria

I have a 1975 Chevy truck with some cab damage(they don’t make repair panels for this location), I was wondering if I could use a 1986 cab for parts. The damage is behind the door on the passenger side of the cab.

Yes in that area everything should be the same so you can use it as a donor.

[82Diesel]

73-80, Different Hood, Radiator Support, Fenders/Inners, Front Bumper that I know of, I know the Glass in the 73-80 Trucks was Thicker than 81-87 and some other little things.

Bed should be the same as Doors, Round hole was until 78? I think The Square came into play in 79.

[1968k20]

Originally Posted by bhc41051

In 1975 catalytic converters were standard on all pickups under 6,001 lbs. GVW

Except the trailering special- my 77 does not have cats

[TKCR]

Seatbelts were different throughout the years.
73-75 were Lap Belts
76/77 was the 1st Style 3pt shoulder belt.
77-86 was the more common 3pt that you see a lot of.
87 they changed the style leading into the next generation of trucks. And the 87, because it changed to a longer lower profile belt, it has to use this extra mounting tab.

[TKCR]

There we a lot of different variations of buckles on the seat belts throughout the years also. My favorite, are the lap belts buckles.
Then there are a couple different styles of plastic buckles.
And then the metal buckles.

[Honest Bob]

Here is what I have learned from putting a 2wd 75 body on an 84 4x4 frame, parting out some of the 73-80 trucks and owning an 84 M1009 CUCV.

1) The very front section of the frames where the bumper mounts are different.
2) I had to drill new holes in the 84 frame to mount the 75 box for the second set of bed bolts from the cab (Never seen this mentioned anywhere!).
3) Dash pads are different.
4) body mounts are different you need to use the ones for the year of your frame.
5) 81+ had thinner glass.
6) Tailgate mounting hardware is different.
7) Gauge cluster wiring dont seem to standardize until 76-77?. 73-75 have an amp meter instead of voltage meter and trying to use different year gauges without redoing the wiring can result in burning wires.
8) Power steering boxes, hoses, and hydroboost units - 73-80 have SAE fittings and 81+ have metric fittings.
9) Windshield washer pumps on the early trucks are built into the wiper motor.
10) Windshield washer buttons are on the dash instead of on the column.
11) High beam switch on the floor until?
12) Steering columns between 73-80 and 81+ use a different spline or D shape (I forget the exact difference but the popular xj shaft mod isnt as bolt on on the earlier trucks as the later ones.
13) Ebrake setups are completely different including the backing plates on the FF 14bolt (not sure about other axles).
14) 73-? use glass fuses instead of the blade type in the fuse boxes.
15) The np205 mount rod between the trans and transfercase stopped being used at some point?

I have friends with 81+ trucks and everytime I think "I have one of those!" the 73-80 stuff I have doesnt fit the 81+. Basically assume the 73-80 parts wont fit the 81-87 and visa versa, they are as different as a similar truck can be. Compatibility does seem to increase with every year but the 73-75 (maybe 76?) trucks are headaches as far as compatibility with the older years.

[Bloodhound]

Originally Posted by Honest Bob

2) I had to drill new holes in the 84 frame to mount the 75 box for the second set of bed bolts from the cab (Never seen this mentioned anywhere!).

I had to drill 2 new holes to mount an 85 bed on an 81 frame (8 foot bed). Never heard of that either!

[Loco83]

Front ends.

[1968k20]

Originally Posted by Loco83

Front ends.

This is awesome

[Honest Bob]

Originally Posted by Bloodhound

I had to drill 2 new holes to mount an 85 bed on an 81 frame (8 foot bed). Never heard of that either!

Oh good! I thought maybe I was crazy.