Exhaust/Filter How many CFMs For My Room

Im getting a 39x39x79 grow tent and want to use 600w mh/hps according to math im supposed to have 16 cfm fan but that doesnt seem to be enough am i doing my math wrong? 3.5'x3.5'x6.5' = 80 cf divided by 5 min. = 16cfm, will that be enough to filter properly, should i get a higher one to filter better or will it only be louder and not help

Your maths is correct. If you can afford it, it is worthwhile getting a larger exhaust which you can run at less than full speed (with an appropriate controller). It'll be quieter and be able to cope better if the ambient temperature is higher.

The grow tent will be in my garage, i live in a housing track so i want smells down big time so i get say a 60cfm filter/exhaust will that be enough to keep the stinkiest buds from giving up my grow house or should i go more based off 80 cubic feet and 6 plants?