390 Ford Truck Tune-Up Specs

by John Stevens J.D.

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The 390-cubic-inch "V8" was one of Ford's most popular big-block engines of the 1960s, and was widely used in passengers cars and trucks. Although the 390 was equipped in some high-performance applications, such as in the Mustang in 1967, the engine was known more for its torque than for its horsepower. For this reason, the 390 was a popular choice as optional equipment in the truck line. Properly tuning up the engine is an important part of regular maintenance, but the specifications must be followed closely, as they often vary by year.

Spark Plugs

The 390 was typically equipped with type BF-32 spark plugs. Those 390s produced between 1963 and 1966 were equipped with type BF-42 plugs. The spark plug gap for all types was .034 inches.

Distributor

If equipped with the manual transmission, the ignition point gap was .021 inches. If equipped with the automatic transmission, the gap was .017 inches. If equipped with the manual transmission, the dwell angle was within a range of 24 to 39 degrees. If equipped with the automatic transmission, the dwell angle was between 26 and 31 degrees.

Ignition Timing

If the 390 was produced in 1962, the ignition timing was five degrees before top dead center ("BTDC"). If produced in 1963 and equipped with a manual transmission, the ignition timing was five degrees BTDC, and eight degrees BTDC if equipped with the automatic transmission. If produced between 1964 and 1966 and equipped with the manual transmission, the ignition timing was four degrees BTDC, and six degrees if equipped with the automatic transmission. If the 390 was produced in 1967 and not equipped with the Thermactor Exhaust Emission Control System, the ignition timing was 10 degrees BTDC. The ignition timing for all other 390s was six degrees BTDC.

Idle Speed

If the 390 was produced in 1962, the idle speed was 515 rpm. If produced between 1963 and 1964, the idle speed was 500 rpm if equipped with the manual transmission, and 485 rpm if equipped with the automatic transmission. If produced in 1965 and equipped with the manual transmission, the idle speed was 600 rpm. If equipped with the automatic transmission, the idle speed was 500 rpm. For all other 390s equipped with the manual transmission but without the Thermactor Exhaust Emission Control System, the idle speed was 575 rpm. If equipped with the automatic transmission but without the Thermactor Exhaust Emission Control System, the idle speed was 474 rpm. For 390s equipped with both the manual transmission and the Thermactor Exhaust Emission Control System, the idle speed was 625 rpm. For 390s equipped with both the automatic transmission and the Thermactor Exhaust Emission Control System, the idle speed was 550 rpm.