GMC V8 engine

GMC shared some engines with other General Motors divisions. But like their straight-6, GMC also has its own line of V8 engines.

Non-GMC engines

Pontiac

Prior to developing their own engines, GMC used the Pontiac V8 engine. They used the Pontiac 287-cubic-inch (4.7 L) motor for 1955 and 316-cubic-inch (5.2 L) motor in 1956, but advertised the engines as the "GMC 288" and "GMC 316". They used Pontiac's 347-cubic-inch (5.7 L) in 1957. For 1958 and 1959, GMC reduced the bore of Pontiac's 370-cubic-inch (6.1 L) to 3.875 in (98.4 mm), resulting in a displacement of 336-cubic-inch (5.5 L). In [[Canada].

Chevrolet Small-Block

From 1955 through 1983, GMC shared Chevrolet's small-block V8. This came in 265, 283, 305, 327, 350, and 400-cubic-inch (4.3, 4.6, 5.3, 5.7, and 6.6 L) sizes.

Chevrolet Big-Block

GMC also shared Chevrolet's big-block from 1968 through 1976. The company used the 366, 396, 402, 427, 454, and 496 cubic inches (6.0, 6.5, 6.6, 7.0,7.4 and 8.1 L) versions.

GMC engines

336

GMC's own V8 was the 336-cubic-inch (5.5 L) OHV/pushrod engine. It used a 3.875 in (98.4 mm) bore and was produced only in 1958 and 1959.

While both the '58 and '59 GMC V8 engines were advertised as 336-cubic-inch (5.5 L), the '58 version was based on the Pontiac 370-cubic-inch (6.1 L), but with a smaller 3.875-inch bore giving 336.1 cubic inches (5,508 cc). The '59 version was based on Pontiac's 389-cubic-inch (6.4 L), but with a smaller 3.78-inch bore giving 336.9 cubic inches (5,521 cc).

305

From 1976 to 1990 GMC produced a 305 cu engine in a 5.0L V8. These engines were well liked due to their better fuel mileage but sold poorly due to lack of power.

In 1991 General Motors started producing their 305 cu V8 engine in a 5.7L along with their original 5.0L V8 which were only produced in the base models of the GMC Suburban, GMC Sierra 1500, Chevrolet Tahoe and Chevrolet C/K 1500. The 5.7L (350 cu in) sold well throughout the 90s because of their better fuel mileage than the 454 cu engine with significantly better power than the 5.0L V8. Production ended in 2000 when GM released its next generation engines that had better fuel mileage and more power than the 5.7L V8.

637

An unusual 637-cubic-inch (10.4 L) 60° V8 was based on GMC's V6 design (basically a 478 V6 with two extra cylinders).