[Amps] wanted source of replacement caps for SB-230 amp

[Fern]

I just recently acquired a Heathkit SB-230 amplifier and need to find a 
source of original style high voltage filter capacitors. They're the type 
with four mounting tabs which are spaces 1 inch apart (opposing tabs)  and 
original specs are 125 mfd @ 400 wvdc but would like something like 300 to 
400 mfd or more for better filtering. Any leads would be greatly 
appreciated.  73 from Fern