Can't guess at what you have without seeing, so can't be sure you've got a rochester carb - but if so, i'm sure they all have a number on the casting - i haven't seen one without it - if memory serves, on the front of the float bowl. Anyway, there will be something on it, post what you have and I'll look up all the spec's I can find - I have an ancient but really good old "Motor" light truck manual that lists all the carb options and their specs for that year.