EFI didn't like big cams, refused to rev beyond the factory air/fuel maps, and didn't get along with injectors big enough to make real horsepower. Then in the mid'80s, computer-whiz John Meaney created a standalone engine management system that controlled fuel and spark independently from the factory computer.
The 351 Windsor, or 351w for short, is one of the greatest engines Ford Motor Company ever produced. Full boosted results-twin turbo, junkyard, sbe 351W. How much power can you make with a junkyard 351W? How to Convert From Flat-Tappet to a Roller Camshaft.
This figure, however, will also depend on cam (i.e. valve) timing. Generally, cylinder pressure for common automotive designs should at least equal 10 bar, or, roughly estimated in pounds per square inch (psi) as between 15 and 20 times the compression ratio, or in this case between 150 psi and 200 psi, depending on cam timing. The Ford 351W or 351 Windsor is classic American muscle. Part of the 90 degree small block V-8 family of Ford engines, the 351 Windsor reached its peak stock horsepower in 1969 at 290. Though this small block is a platform capable of much greater performance, you can easily modify it to make more horsepower and torque.