throwing some "hard" analysis at it, the pre of '74 was certainly not over-rated ( theoretically ) :
from wiki :
http://en.wikipedia.org/wiki/Steve_Prefontaine
1,500 meters 3:38.1 28 June 1973 Helsinki, Finland [2]
2,000 meters 5:01.4 9 May 1975 Coos Bay, Oregon
3,000 meters 7:42.6 2 July 1974 Milan, Italy
5,000 meters 13:21.87 26 June 1974 Helsinki, Finland
10,000 meters 27:43.6 27 April 1974 Eugene, Oregon
1 mile 3:54.6 20 June 1973 Eugene, Oregon
2 miles 8:18.29 18 July 1974
3 miles 12:51.4 8 June 1974 Eugene, Oregon
6 miles 26:51.8 27 April 1974
5000 meters (H.S.) 13:52.8 1969
trying a calculator
http://www.jundo.co.uk/
( & remember he was born in jan '51 - making him only 23y in '74 - he wouda been expected to improve in '75, '76... ) & some commonsense : round up any 10k pb to next quicker 5s multiple for assumed sub-optimum pacing/conditions/etc - assume 27'43.6 is
27'40
then 27'40 with various assumed 400 ability at the time :
53.0 -> ~
1'51.8
3'39.4
3'56.6
4'58.5
7'40.5
8'16.4
13'14.0