IMHO you should prepare for smoke! Something is wrong, the set should not be drawing enough current to get an 18 ohm 25 watt resistor *really* hot!
Calculator:
http://www.crownaudio.com/ohms-law.htm
If you plug in 18 ohms and, say 15 watts (my estimate of what it might take to get a 25 watt resistor fairly hot), you will find a voltage drop of about 16.4 volts (too much drop) and a current of about 900 ma! Since the original rectifiers were only 340 ma or so, it would appear that the set is drawing more current than it should,
just my 2 cents,
jr