Thanks for the info guyz.
The 351 Cleveland is a slightly wider engine than the 351 Windsor, but the way that the C exhaust comes out.... (the head exhaust surface is 90* to the deck.... the W is not....) makes the C exhaust come out pointing down at a 45* angle and the W points out more sideways. In a tight compartment the C actually fits better and has more exhaust header clearance. So, believe it or not a C goes into early 60s unibodies easier than the W.
I have never seen a C in a late 50s Ford.
Anyhow here is the photo I mentioned.
check out www.readershotrods.com