This family of engines includes the 390, the 427, and the 428, all which are found in performance applications. The latter two are quite different, despite the similarity in displacement. The 428 was the basis for the "Cobra Jet", used in Mustangs and Fairlanes from 1968 through 1970. This engine has a long stroke which enhances low end torque and makes for an excellent street package. The 427 is a high RPM, large bore/short stroke engine that was the mainstay of Ford's race efforts in the mid-60's. These engines have become collectors items in recent years, and are rarely seen in active competition. Newly available reproduction blocks and heads have renewed interest in this engine, particularity for use in replicas of the Cobra sports car. The 390 is a smaller bore engine which shares the 427's short stroke. It was produced in large quantities as a moderate performance engine for passenger cars, as well as for truck applications
through 1975, and is the most common of the three.
Many parts such as heads or crankshafts can be interchanged between engines in this family, but carefully check for interference between valves, pistons, and the block if you stray from the factory combinations. When building an FE engine for street performance or towing it is best to emphasize low RPM torque, rather than high speed power. When using most available cylinder heads, these engines respond well to fairly small tube headers, conservative carburetor sizes, and camshaft selections which target a 6000 RPM maximum. This is particularly true of the 390 engines. If you are fortunate enough to obtain a set of expensive and rare Medium Riser, Hi-Riser, or
The compression ratios shown in this catalog are calculated figures, not factory advertised numbers, and may vary from previously published data. We have not changed the pistons, only the way in which we calculated the ratios. All FE engines have full floating pins from the factory.
When camshaft selection and vehicle use becomes more race track oriented, the valvetrain should be upgraded. Any FE engine can be converted to an adjustable valvetrain through use of the proper rocker arms and pushrods. The adjustable rockers have a slightly higher ratio than do the nonadjustable ones, so check piston to valve and valve spring clearances when making this change. The factory rocker shafts are prone to breakage in racing use, thus aftermarket parts may be required. Also recommended are "end stands" which support the outer portion of the shafts. Some of the lower output engines have two piece valve spring retainers, which should be replaced for performance use.
When using solid or roller lifters in these engines it is common to block off or restrict the oiling to the lifter galleys. The factory 427's with solid lifters did not directly oil the lifters, so this should not be a problem. Another frequently seen oiling modification is matching of the main oil passages to the holes in the bearings. These are frequently offset by quite a bit from the factory. It is also common to open up the inlet passage at the oil pump mounting area to match the outlet on the pump. Whether these changes really help is open to debate, but they certainly don't hurt.