NO LONGER AVAILABLE Listing ended Oct 5, 2026

1978 GMC C/K Series

$10,495

Vehicle Details

Make

GMC

Model

C/K Series

Year

1978

VIN

AMS37437

Body Type

Pickup Truck

Transmission

Automatic

Engine

350

Description

1978 GMC 3/4 ton all factory power options 350 4v automatic a/c tilt wheel power window power locks new rims new tires.

GMC C/K Series Buyer's Guide

Full guide

Robert Halloran

Classic Trucks

1960–1991

~3 min read

Updated Apr 2026

The GMC C/K Series covers every payload class of the professional-grade truck lineup, from the half-ton C15 through the one-ton C35, giving buyers a complete picture of the most capable and best-supported classic truck platform in American history.

This guide covers

✓ 8-point inspection checklist

✓ Common issues & what to avoid

✓ In-person inspection guide

✓ Market pricing by year & condition

✓ 4 FAQs answered

✓ History & fun facts

Read the Full C/K Series Buyer's Guide

GMC C/K Series Market Overview

Based on 16 GMC C/K Series listings currently on ClassicCarsArena.com

Listed Now

$19,502

Avg. Asking Price

1962–1986

Year Range

Price Position on Our Site - Average Range

This car: $10,495

Low: $7,995 High: $50,995

Transmission Distribution

Automatic 63% ◄

Manual 6%

Condition Distribution

Excellent 19%

Good 19%

Data from ClassicCarsArena.com listings Browse all 16 listings →

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GMC C/K Series Buyer's Guide

Robert Halloran here. When most people think about the classic GMC C/K, they think about the half-ton C10/C15, the truck that's become the darling of the restomod scene. That's a fine truck. But the C/K Series extends well beyond the half-ton, and some of the most interesting, and undervalued, examples wear the C25 and C35 designations. Three-quarter-ton and one-ton GMC trucks were the backbone of small business America for thirty years, and they deserve a proper buyer's guide of their own.

The C/K platform ran from 1960 through the end of the classic era in 1991 (the OBS generation continued to 1998, but the pre-1991 trucks are the collector targets). In that span, GMC built a complete range of work trucks that shared the same basic architecture across every payload class while offering genuinely different capabilities. Understanding the full family makes you a smarter buyer at any price point.

What to Check Before Buying

✓

Frame Rail Inspection , Inspect full length of both frame rails for cracks, one-ton trucks bear real stress and crack at predictable weld points.

✓

Rear Axle Type , Identify rear axle (14-bolt GM full-float = 1-ton; Dana 60 = heavy 3/4-ton), verify it matches claimed payload rating.

✓

Rear Spring Sag , Check rear spring pack for sag, overloaded springs deform permanently and are expensive to replace.

✓

Front Dana 60 (4WD) , Inspect front axle U-joints and check for seal leaks, heavy 4WD use wears front axle components faster.

✓

Cab Corner Rust , Probe cab corners, universal on northern-state trucks regardless of payload class.

✓

Floor Pan & Rear Cab Mounts , Check floors and rear cab mounts on Squarebody trucks (1973+).

✓

6.2L Diesel (if equipped) , Test glow plugs and check for injection pump leaks, cold starting should work within 30 seconds at 50°F.

✓

Powertrain Codes , Decode firewall tag for engine and payload class, verify it matches claimed specification.

Common Issues

Frame stress cracks on one-ton trucks used for heavy towing, inspect the full length of both rails. Overloaded rear spring packs that sag permanently. Rear axle seal leaks on the 14-bolt GM full-float rear axle. Front axle wear on 4WD trucks from heavy use. Cab corner and floor pan rust identical to half-ton trucks. 6.2L diesel injection pump failures and hard starting from glow plug system issues.

What to Look For

Inspect the frame rails on heavy-duty trucks carefully, one-ton trucks were used for actual work and accumulated real stress. Check the rear axle for seal leaks and verify the axle rating (a 14-bolt GM full-float is correct for one-ton; Dana 44 rear means a lighter-duty application). On 4WD trucks, test front axle engagement and inspect the front Dana 60 for worn U-joints. Verify the heavy-duty spring rating (overloaded springs sag and cause uneven tire wear). Check the cab for the same rust patterns as all C/K trucks: cab corners, floor pans, rear cab mounts on Squarebody trucks.

Price Guide

1960–1966 C/K Series three-quarter-ton: $10,000–$22,000. 1967–1972 C25/K25 with big-block: $18,000–$38,000. 1973–1987 Squarebody C25/C35: $8,000–$20,000. One-ton dually (DRW) variants: add 15–25% premium. 4WD adds $3,000–$7,000. 6.2L diesel models: add $2,000–$5,000 novelty premium. Heavy-duty trucks typically sell at 20–35% discount to equivalent half-ton C/K trucks.

Did You Know?

The GM 14-bolt full-float rear axle in one-ton C/K trucks is rated at 10,500 lbs gross axle weight, the same axle that military 2.5-ton trucks used in modified form. The 292ci inline-six was used continuously in GM trucks from 1963 through 1990, a 27-year production run for an essentially unchanged design. Some fleet-operated one-ton Squarebody trucks have documented mileage exceeding 500,000 miles on original engines.

$10,495