The other thing about seleniums is that they've got quite a voltage
drop, part of the replacement procedure was adding a power resistor in
series to get the proper voltage to match the original selenium setup.
An 80 amp power resistor might be a little spendy.

How about an extra diode in series with the output after the bridge?
This will drop the voltage about 1v under heavy load. Better be a
big diode with a heat sink though. This also protects the bridge
if someone hooks up the leads backwards. Without this diode, connecting
the leads to the battery backwards will provide a short circuit across
the transformer secondary. Been there, done that, replace the bridge
and added a fuse for the next time. A diode would have been better
than a fuse, but the extra voltage drop was too much for my transformer.