I have a stock 1978 Chevy 400 SB out of a half ton truck. This motor has under 40,000 miles on it. Has 50-60 psi of oil pressure cold and 15-20 psi warmed up at an idle. Motor will come complete (all accesories to flywheel, pan to carb) Engine identification number is 3951509. Let me know if there is any more info that you want. Asking $500 OBO
The only block of this family, 400 cu in (6.6 L) small-block, was introduced in 1970 and produced for 10 years. It was loosely based on the medium journal 350 and had a 4.125-inch (104.8 mm) bore and a 3.75-inch (95.3 mm) stroke. The 400 differed from other small blocks in that the cylinders were siamesed, used a 2.65” large journal, and often times had one more freeze plug on both the left and right sides of the block. Initial output was 265 hp (198 kW) and was only available equipped with a 2-barrel carburetor. In 1974 a 4-barrel version of the 400 was introduced, while the 2-barrel version stopped production in 1975. 1976 was the last year that the 400 was used in a Chevrolet Passenger car, available in both the A-Body and B-Body line. While popular with circle-track racers, the engine was prone to cooling troubles if cylinder heads without steam holes were used. They mostly put out 250 hp stock. Due to the way the block was designed, the 2 bolt main engines were stronger than the 4 bolt versions if properly prepped. The 509 2 bolt main block is the most desirable 400 block
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