Here is a before and after pair of pics of the amp chassis. All I did was replace the 4-section cardboard tube filter cap with 4 individual electrolytics. I installed a terminal strip to mount them. I usually change out the coupling caps, too, but apparently I didn't here. Does this look like your chassis?
That Beitman's schem is very difficult to read, but really all you need to do is replace value-for value.