Hammond choke max dc rating?

[azatplayer]

I just ordered and received a couple of Hammond 158L chokes for some builds im planning. The first rocket i did was a mod on a Twin that i didnt like. It was an EL34 based twin that didnt work for me. So in the conversion to rocket i discovered a truly great sounding amp. Im using the 3 henry choke i originally had setup in it.
I have another amp i built for my brother that i converted to rocket as well. It has a Hammond PT that gets me about 430V on the plates of the KT66's.
Did the conversion sans choke, and while good, is not quite there. So i got a couple chokes which turned up today.
Looking at the info on the box, and i see they are rated for 400V max operational voltage. As im gonna have 30V or so above that, im wondering is the 10 percent rule gonna be ok? Or do you guys think 400V really shouldnt be exceeded?
Cheers in advance!

[David Root]

I have used a lot of Hammond chokes and they are pretty forgiving. Hammond typically are pretty conservative in all their ratings. I wouldn't worry about it unless you are feeding it from a very large power supply cap >100 mf, which might spike the voltage and current coming off standby.