heavy breathing
ScotRod you have obviously been doing your homework. The 360 does have more potential by a long shot, over the 351W, when running stock heads.
There again the biggest drawback is with the 360 being over 100 lbs heavier.
I know this may sound strange, but if I had no engine in my vehicle, and had a choice of these 3 engines and limited resourses to work with, I would go with a 351M, as of the three, it has the most potentia. Theres just no way to get around those awesome Cleveland heads, and the M block is only 50 lbs heavier than the Winsor.
That being said, any of those engines can be made to get up and move.
I wouldnt have a problem building a 360, at all. Being that is a truck engine, the biggest drawback is the compression.
If a major overhaul is in order, 390 Pistons are the same as for the 360, and there are a myriad of those on the market. However, a simple .030" cut off the deck of the heads would yield a good 9.5:1 compression, and that would be about as high as I would go with any street engine.
As for intakes, naturally a dual plane 4 bbl intake is the order of the day, however since its not a 6000 RPM engine, I would elect to go with a carb in the neighborhood of 550 to 600 CFM, vacuum secondary. An aluminum intake will drop about 40 lbs off the weight of an FE block on average.
The FE heads were notorious for good flowing from the factory and I would only do a mild bowl blend on them, and if they have the air injection tonsil in the exhaust port, would grind that out first.
I would run a cam in the neighborhood of 210-220 degrees duration at most, Since with an engine of that displacement, when you start getting over 220degrees, you start getting into cams that are more for high rpm, and lower end torque will start to suffer, and lower end grunt is what an engine needs 99% of the time, especially for stop and go driving, and hauling loads. even running the stock cam isnt all that bad if some of these other things, like good exhaust, a little more compression, some mild port work, and a good intake and carb are applied. Its not difficult to add about40 hp with those things alone. The same applies with the Winsor and M block as well.
On defense of the Winsor, dont let the small valves fool you. Those heads, while having small valves and a somewhat restrictive exhaust port in stock configuration are very efficient. The key there is to know what you are dealing with and how to make it work best. It is not that difficult to get 1 HP per cube out of a "stock" head 351W, going with 1.94/1.6 valves will help a lot if you have ported the heads out, but going to the larger valves in them selves wont see a thing over stock, if you havent worked the heads over. Going to larger valves, IE 2.02/1.60, requires flycutting the pistons to clear the valves, the 1.94 being as large as you can go with the stock valve reliefs.
Also keep in mind that the smaller valves along with the smaller passages make for some nominally better bottom end power as your velocities are higher, with the fuel air mixture, and unless you are running an open chamber head, going to the biggest valves can actually hurt you due to shrouding, on production heads. Your cam choice of 224 degrees with 110 lobe separation is a good choice, that being as big as I would go though. The narrower lobe separation definatelly has it advantages for bottom end power.
Rule of thumb, when looking at cams. Figure what you want for peak RPM then get a cam that has its power band about 500 to 1000 RPM lower. Remember that a stock cam in the earlier engines usually had a power band of 0-3500 and the engines often made their peak power at around 1000 rpm over that. A classic example of this was with the 271 and 306 HP 289's. They ran a solid lifter cam with 228 degrees and put out peak power at over 6000 RPM. When comparing cams, it generally takes 10 more degrees of duration on a solid lifter cam to operate in the same power curve as a hydraulic lifter cam.
IE a 240 degree solid lifter and a 230 degree hydraulic, generally have the same power band.