This article is a bit dated, but it outlined the conversion factors for Track and Field during the Canadian CIAU (now called CIS) in the early 1990′s.
The standards to qualify for Nationals were based on the 8th place performance from the previous year’s Finals.
I am often surprised by the number of people asking for conversion factors for Track and Field. Basically, I’m referring to athletes wondering the extrapolation of a 60 meter time to 100 meter time. Or a 55 meter (a common distance at Dartmouth College in Hanover, New Hampshire) to a standard 60 meter.
I guess taking intermediate splits would be considered interpolation?
I already posted an in depth look at the differences between a 400 meter and a 440 yard
The best way to determine your time is actually running that distance. Or, have official splits taken along the way.
It was reported Ben Johnson splits in his ill-famous 9.79 100 meter race in Seoul was 5.52 seconds for 50 meters, 60 meters in 6.37, both of which were under the current world records for those distances. He also went through 40 yards in 4.38 seconds.
Here are some Track Conversions tables for rarely held distances.
The interesting conversion is the 200m to 300m conversion where you add 13.1 seconds. My 21.98 PB translates to a 35.08 (but my PB for 300 meters indoors was 35.15)
Do these add up for you?
50y -> 50m = add 0.64
5.16 -> 5.80
50m -> 55m = add 0.55
5.80 -> 6.35
55m -> 60m = add 0.54
6.35 -> 6.89
50m -> 60m = add 1.09
5.80 -> 6.89
400m -> 440y = add 0.3 sec
48.54 -> 48.84
300y -> 300m = add 4.1 sec
30.64 -> 34.74
200m -> 300m = add 13.1 sec
21.64 -> 34.74
Here is a conversion caculator that is very easy and I find very accurate.
http://www.howardgrubb.co.uk/athletics/wmalookup06.html
Hope it helps