Travis, I'll bet if you put your 37 amp alternator back in your car, it will quit blowing that fuse. Reason I think that, is your old alt. was probably marginal, in its ability too keep up with the amp draw on it. Your new hopped up electrical system now has more amps to draw from. I think your duel fans probably draw more than 30 amps, blowing the fuse. If you don't want to try a bigger fuse, you can protect the circuit with a fusable link. Most high amp circuits on an automobile are protected by fusable links, (starters, fans, Headlights, etc.) They are just getting more amps with the bigger alt. cause there are more available to draw from. Bet your fans spin faster, and your headlights are brighter too,with the bigger alt.
Hope this helps, good luck