The heads were the biggest difference. The Cleveland had some massive flowing heads compared to a stock Windsor. Also the Cleveland tended to have higher stock HP ratings, although both engines were able to be highly modified and produce some very good HP and torque numbers. The cleveland was built with 2 different types of heads, 2 valve and 4 valve heads. The 2 valve are better for building a streetable moter, and the 4's tend to be better for a strictly racing motor, although you could really use either one. I don't know quite as much about the Windsor, except it had much higher production numbers than the Cleveland ever did. An easy way to tell the difference when looking at the two, the Cleveland Valve covers have 8 bolt holes, where the Windsor only has 6.
I believe the highest factory rated 351W engine was the "M" code used in the 1969 - 1970 Shelby Cobra GT 350. Even so, it was only factory rated at 290 Gross HP, with 385 ft/lb of torque.
There were no 351W high performance heads from Ford. The 351W 4V and 2V used the same heads. Only difference are the valve springs. The 351W '69-74 heads are a good replacement for the stock 289 or 302 engines.. Valves are 1.84/1.54.
The Cleveland was a different animal. The 1971 "R" code 351C Boss was factory rated at 330 Gross HP, with 370 ft/lb of torque. That factory rating was very low, a well known joke.
No parts of the Cleveland engine will interchange with the Windsor small block. The engine can be identified by the thermostat, as it is mounted horizontally in the timing chain housing on the the front of the block, not in the intake manifold as on the Windsors. The '71 Boss, '71 CJ, '72 HO, and '72-73 4V blocks had four bolt mains.
The Cleveland had either 2V (closed chamber) or 4V heads. Most of the 2V heads have 2.04/1.65 valves. The 4V heads had huge 2.19/1.71 valves.
Well, let me check my notes and see what I can remember about the 289 engines..
I will assume that you are talking about the 289HP model, which is similar to a standard 289 except the main bearing caps were thicker. They used the same size ports, CC's and valves (except for select castings) as the base 289 heads. Main difference were slot guided push roads, and screw in rocker arm studs. They also used a HD connecting rod with 3/8" bolts.
The 289HP was produced from (I believe) 1963 - 1968.
Heads ranged from a cc of 49.2 to 54.5, depending on casting numbers. The 49.2 cc heads had 1.67/1.45 valves, while the 54.5 heads used 1.75/1.45 valves.
The highest factory rating for the 289HP was in the 1967 Shelby GT 350, and had an engine code of "2". It was rated at 306 HP and 329 ft/lbs with a compression ratio of 10.0:1.
The "standard" 289-4V engine during the 1963 - 1967 period had a rating of 225 HP and 305 ft/lbs, and had engine codes of A-C. The 289HP engines (other than the Shelby unit) had a rating of 271 HP and 312 ft/lbs.
Another point of confusion with the windsor\ cleveland motors,the 302 windsor is a different block to the 351 windsor, the later being wider ,heavier and an inch taller.But some of the heads are interchangeable.The 302/351 clevelands are generally the same block,different stroke ratio's,and heads are interchangeable
Good info but i will also add some.SVO8 there is no 302 Cleveland in the USA as thi s is a stroked down 351 made in Australia/NZ only.s-code the 2V -4V is for 2 venturi or 4 venturi instead of valve.P71Times2 there is some interchangability among the Windsor and Cleveland as the bore size and spacing is identical and the head bolt pattern is the same then the heads from a clevo can be put on the windsor and we have this in one of the mustangs which is the Boss302 (Windsor block Clevo heads)Part of the reason for the large heads and good breathing on the clevo is the staggered valve arrangement which the windsor doesn't have.Hope you guy's aren't thinking I am being a smart arse by correcting these small points as you have all put up some good stuff.The Cleveland is a brilliant engine.