yes they will fit but not without intake/ water jacket modification. The intake being altered(clevor style intake) will do away with your fuel injected dream......also , it is kind of a waste of time since they have aftermarket windsor style heads that outflow cleveland heads without you having to modify anything
thats what your boss 302 from 69 and 70 was. You could run fuel injections, it would just take some modification to the intake manifold. Weld up sup bungs for the injectors, a tbi style throttle body.
See http://www.pricemotorsport.com/ for some adapter plates to match the Cleveland heads to your 5.0 Windsor EFI manifold (AP-09 cost is $255.). If you can get the Cleveland heads for $50-$100 a pair, this can be a budget upgrade. Figure putting $250-$325 into a rebuild and have hardened valve seats put in, since the non leaded fuel requires them.