1996–2002 Chevrolet Express/GMC Savana full-size vans TBI L31 applications 1996 G-Series vans over GVW w/ 4L80E transmission Special applications Oscar Mayer Wienermobile 1995-2003 GMC W4500 Tiltmaster / Isuzu NPR gas 4.125 in bore family (1970–1980) 400 The is the only engine in this family and was introduced in 1970 and produced for 10 years. It has a bore and a stroke. The 400 differed from other small blocks in that the cylinders were siamesed and therefore required 'steam' holes in the block, head gaskets, and heads to help alleviate 'hot-spots' in the cooling system at the point above the siamesed cylinders. Overheating and damage are likely if head gaskets or heads without 'steam' holes are used on a 400 block. The 400 is the only engine that uses a main bearing journal and a rod bearing journal. The connecting rod was also 400 specific being as opposed to the rod used in all other small block Chevrolet engines. The 400 was made in 4-bolt main journal from 1970 to 1972 and in 2-bolt main journal from 1973 to 1979. The 400 can have either 2 or 3 freeze-plugs per side though all 400 blocks have the provisions for a 3rd freeze-plug on each side. The 400 was rated at gross ( SAE net) through its life. The 400 saw extensive use in full-size Chevrolet and GMC trucks; K5 Blazer/Jimmy, 1/2-ton, 3/4-ton, 1-ton, and even larger 'medium duty' trucks had an option to be equipped with a 400. The engine was available in midsize A-Body and full-size B-Body passenger cars until the end of the 1976 model year. Early models produced with a two-barrel carburetor. All 400s came with a two-barrel carburetor until 1973. A four-barrel carburetor option became available in 1974. The 400 was never intended as a high-performance engine and never saw large factory horsepower numbers; nevertheless, it developed a reputation for creating tremendous torque (up to in 1970) and has since become popular for many types of racing, both on- and off-road. It was also used for the limited production Avanti for a few years in the 1970s. 3.671 in bore family (1975–1976) 262 The 1975–1976 262 was a 90° pushrod V8 with an iron block and heads. Bore and stroke were . Power output for 1975 was at 3600 rpm and at 2000 rpm. The 262 was replaced with the 305 for the 1977 model year. This