if it has the 24" radiator, the answer is no, at least not without a lot of modification and fabrication anyway. the 20" will fit with minor work, check out mustang steves website, he goes into a lot of detail about the 20" swap, here is a direct link
my dad put a 70 in his 68 all he did was frab the brackets of the frame rails of the 70 weldthem on and grab the bracke of the top and put them to hood latch bolts i dont know if they are the same on the 65 but it shouldnt be that hard if u can weld. u might also want to put some radiator hose btween the rad opening and the rad they get kinda close