Time/current charachteristics for automotive fuses are here:

http://www.littelfuse.com/products/fuse ... Delete.pdf

Can't find it for the higher fuse ratings but the curves wont change just where they are on the graph. If you scroll to the bottom you'll see the curves.

Basically for a 1A fuse you get:

Instantaneous: 10A
0.1s: 3.5A
1s: 2A
10s: 1.5A
100s: 1.25A
1000s: 1.15A

Approximate figures because the graph isn't too accurate but interpolating (which in the case of fuses is perfectly valid but doesn't give a fine accuracy) that to a 100A fuse you get:
0.1s: 1000A
1s: 200A
10S: 150A
100s: 125A
1000s: 115A

In practice they are designed to take the peak current if they're sized to take the running current. We've used a 20A fuse on two drills and a set of gimsons in BOOM! since it was built. I put a 25A fuse in Diablo and it runs no probs. Will be interesting to see wether it holds on the Wyachi's in combat but I suspect it will.

Andy