FWIW, I've got experience with two 351C-to-351W conversions (two Pantera buddies), and both happened because the Clevelands suffered catastrophic engine failures. The first ate its #7 rod bearing (and digested it through all the
oil passages), and the second dropped a valve -
that was some impressive damage! The bearing problem was attributed to a (well known?) Cleveland oiling problem, although what specifically about the oiling system causes it, I don't know. The valve problem is also apparently well known with stock valves - I think the stems are hollow and prone to breaking.
Also, it's recommended that the 351C blocks not be overbored beyond .040, so finding a usable old one may be difficult, whereas the Windsors are supposed to be fine at least to .060. The Cleveland heads are pretty impressive, at least in port and valve size, but given the number and variety of available aftermarket Windsor heads, that isn't a compelling argument for the Cleveland anymore.
IMOSHO :-), the only benefit to going Cleveland instead of Windsor would be for style points. With the aftermarket support for the Windsor engine family, I'm guessing it's easier and cheaper to get more reliable horsepower from the Windsor.
JLW
Clevelands and Windsors
Threaded Mode
