[codefox1]

Yes, radio output tubes are not all that fussy about impedence matching, you would be good with anything from 4 to 8K to your speaker load for single ended 42. If you have a Push-Pull that has a primary in this range, you can use it, just tape up the middle tap of the primary, or just use one leg of the primary if it is a closer match. Any slight mismatch would only minimally affect the volume and would not cause any harm. Anyway, if you are not happy, you can always change it out for another one.