Those T-Birds were prolly the hottest CPU's ever made, I think they were called AMD Chernobyl

70c sounds kinda hot but for a T-Bird it's about right in a standard pre built of its day, should try and get it down to 60c at least.

The coolers in this thread should work good http://www.techzonez.com/forums/showthread.php?t=13794 make sure you get a HSF for Socket A