351 C vs W
I had a '70 mustang, came with a 2V - Cleveland... never ran since I owned it. 4 Spd manual tranny. I got rid of the car, but kept the engine, as I'd already had it rebuilt for $$$. I wanted to keep the Cleveland, pretty much as is (flywheel/flexplate), which led me to my '70 XR7 (351W-2V, 4 spd).
Clevelands are sound racing engines (see fastest lap turned in NASCAR... Bill Elliot - 351C, but definitely not stock) They are high revving and like to turn RPMs due to the cylinder heads. 2V heads are considered better for street... my argument is "will 4V heads have more torque at 1500 RPM than, say, a 3.8L"... I'd guess yes. Windsors can be built however you like 'em.
Personally, I liked the mystique of the Cleveland. Parts are harder to find, but not that much harder. For the most part, more expensive, as well. Not as many aftermarket parts available, but the heads are still beautiful. I equipped mine with a custom Crane Roller Cam (224 intake, 232 exhaust duration, .584 lift intake, .604 exhaust, 110 separation), roller rockers, MSD Ignition, Weiand Excelerator Intake, now 4V heads as my 2V were cracked... regardless, why I wanted to keep the Cleveland.
Windsors are easier to hop up, cheaper to hop up, and lighter. You are afforded a little more engine bay room (side to side), and supposedly get better fuel economy. Maybe you should just give your old Cleveland to me . Windsors can also be made lighter, more easily, presently, as the only aluminum heads I'm aware of for the Cleveland are Aussie heads. I'm going to drop the Windsor in my '66 Mustang coupe... have to replace the flywheel in the rebuild, tho.
Bellhousings should be the same, I understand. If so, you shouldn't have to worry too much about fitment. Be conscious of, if you swap, if the old engine is a manual transmission (flywheel) as opposed to automatic (flexplate).
Guess it boils down to whatever floats your boat (or squeals your tires... )
1966 Emberglo Mustang Coupe
1970 Avocado/Black Vinyl XR-7