Hi schmuu,
zubbly is the resident fieldlines master of motor conversions. His rule of thumb is that you can get about 150 watts output per cubic inch of magnet material. A 4X1X0.5 mag is 2 cubic inches. 4 of these is 8 cubic inches, or 1200 watts. 8 would be 2400 watt output.
If you plan on using these magnets, you will have to skew the laminations and completely rewire the conversion to eliminate cogging. The magnets are simply too long to be able to skew them on the rotor without a huge airgap. (A massive effort - my advice, if you are going to completely rewind and skew laminations, build it to the max potential. IE, don't use these magnets on this conversion.)
(If you really insist upon using these magnets, dinges has been doing some research on a different style of skewing that you could use. It's a little more complex than zubbly's method of skewing, but it appears to be a workable method.)
Check to see how many lead wires are coming out of the motor presently. We have a similar motor here on the farm, with 12 wires coming out. If you have 12 lead wires coming out, use the windings you have. That's the easiest solution. You can get away with just building a rotor for the motor. With 12 wires coming out, you can adjust cut-in speed by how you connect them.
I'd recommend using a skewed line of round magnets on the rotor for each pole. Decide how many watts max output you want, and divide by 150 to determine how many cubic inches of mag material to use.
Once you know what kind of output you want, look at a chart of available power in the wind to determine what blade size you will need to use. Also, look at a chart showing what winds your area gets. If you build a genny to generate power at 50 MPH winds, you're going to be SOL since the Akron area doesn't get many winds like that.