Oil change and radiator question

I have a 65 inline 6 240 in my supervan. Is there a dipstick on these at all? If not how do you tell when you're low? How much engine oil will it hold empty? Also what is the capacity of the stock radiator?

a lot of questions i know. Thank you!!!

I see a dipstick hiding between the distributor and fuel pump,,,,,,,oil should be 5 quarts with a filter change,,,,,