351W vs 351C
 

What is the difference between the Windsor and the Cleveland? I know one is a big block and one is a small block but they are the same cubic inches, so what makes one a small block and the other a big block?

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James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft

Well, not quite. Both are "small blocks" (there's also a 400 small block and a 351m for modified version of the 400 with a 351 length stroke - they DO share the same bellhousing pattern as the 385 series big blocks) The real major difference is in the head design. The Cleveland has "small" 2bbl heads and "big" 4bbl heads - only thing is both of them are "big (valve)" heads. All except some of the 4bbl heads are open chamber and therefore not overly efficient from a combustion & detonation resistance standpoint. However, with big valves and ports, they flow like gangbusters - even the 'small" 2bbl heads. Problem is they're just about too big for a street motor - especially the 4bbl heads. Too big valves and ports kill low and mid range torque and throttle response. So, they're great for hi rpm racing, but not so good for the street. With the WIDE selection of really good heads for the 351W's out there, the W's can be built from mild street to REALLY hot track/strip and, at the same level of performance, will at least match if not beat the C's. Also, lots more parts available, wider selection of intakes (no efi for C's) and cams, etc etc. Windsor block (especially the new reasonably priced Sportsman block from Ford) is a little sturdier and does have a better oiling system. C blocks in extreme use like to crack internally. They're still really neat engines and can really perform - they're just not as modern a design from a head standpoint as the W's now that the W's have such a large selection of excellent aftermarket heads.

A Windsor block stronger than the 351C. Oh man, you kill me!

Now first of all the Cleveland's that have the problems with block cracking were the later variety. The mid 70's and later, not the early 70's blocks. The blocks, as you have addressed had an oiling problem, which amounted to Ford being overly concerned with everything up top getting the crap oiled out of it. To be better with the oil dispersion they use a oil passage restrictor to keep the oil pressure up and good for the low end too. That eliminates the oiling problems.

The 351C does sacrifice low end for high end power. With 2.19" intake valves, and 4v heads that flow almost 300cfm, even the stock Cleveland heads provide the same flow or greater than a pro ported 351W set. The Cleveland's block was meant to take the abuse of higher revving power too.

All in all I'd say the 351W and the 351C are more like a 5.0 and a 4.6 DOHC motor. The 351W has parts readily availible, makes better low end power, can be turned into a real street machine, but it can't match the potential of the 351C, and stock for stock, 351W's need some mods to compete on equal ground.