I used to use ones that came out of 140 hp Mercruiser stern drives. The engines I put them in ran fine. People really flog this condenser subject to death but my motto is, if it fits, it ships.
According to reference info that I have your condenser (capacitor) 399-123 Scintilla is rated at .17 to .21 microfarads. You can use any capacitor in the size range. Modern electronic condensers work good. Or any of the Merc Scintilla mags use the same cap. , the Mark 20 about the most common. On the OMC side, the Big Twins 51 – 56 ( pt 171471) use .20 mf cap.
Hope this helps
Like you have heard from others….you can use various caps that fit physically and have the right electrical specs. If you want to consider the solid-state capacitors that many of us have found to be superior in stability and longevity…here is a link to a popular source. This link is for 0.22uf but the same vendor has other choices as well.