Hey Ford guys... Question for you.

[prototype]

Big differece between a 351W and 351C

351W is a physically smaller motor and utilzes the same valve covers that a 289 does. 1969 Mach 1 Mustangs had the 351W in them.

351C is larger and breathes much better. The Boss 351 is based on the Cleveland motor.

Ford tip of the day
The easiest way to tell if a Boss 302 or 351 has an original Boss engine is screw in frost plugs.

[mssl72]

"Ford tip of the day
The easiest way to tell if a Boss 302 or 351 has an original Boss engine is screw in frost plugs."

If I unscrew them to check will they get mad?

[PeteLeathersac]

I'm no Ford expert but didn't the Windsor motors have the bolt on aluminum timing chain cover/assy. and the Cleveland an extension of the block w/ steel cover plate? . I seem to recall some Torino/Montegos w/ engine application stickers noting 351-C too but were really the 351-M Modifieds and easy to tell as all M motors had the big 429/460 bellhousing pattern? . Again no Ford expert here....don't claim to be, don't wanna' be and never will be. ~ Pete

[WWMCMike]

The 351 Windsor and the 351 Cleveland are completely different other than both use a 3.5" stroke crank and both have a 4.00" cylinder bore. The 351W has a 3.00" main bearing while the 351C has a 2.75" bearing. The 351W has a 9.5" deck height while the 351C has a 9.2" deck height. As stated earlier, the 351W utilizes a bolt on timing cover while the 351C has the timing cover cast into the block and uses a flat cover plate. And of course, the cylinder heads on the Cleveland are a canted valve large runner design, while the Windsor uses an inline valve design with small runners same as used on Small Ford V-8's from the 260, 289, and 351W. Both use the same Ford "4 Bolt per Cylinder" head bolt pattern.

The Boss 302 took a 4 bolt main 302 Windsor block, uses a bolt on timing cover, and adapted the 351 Cleveland style heads. The Boss 351 is an entirely Cleveland based engine.

Hope this helps.

Mike McCullough