7-gallon pots?

Think I could get away with 7-gallon pots in a 39x39x79 tent?

You could probably fit 5 pots in there, just guessing, since you didn't give dimensions, but remember, your plants are going to exceed the diameter of the pots, so if me, I would plan on 3 at the most, unless you plan to grow shitty plants.
3 will give you room to turn them, inspect, water, check leaves, etc.

Yeah I was gonna do 3 plants just wondered if 7-gallon pots would be too much

you must be going after massive yield with 7 gallon pots. if you want my 2 cents. I fuck around a lot used 3 gallon smart pots vs 5 gallon smart pots no difference in yield. and 5 gallon vs 7 same yield. veg for 3 feet tall. then flower average 4 zips a plant. putting 6 under a 600 lamp. mabe this will help you out. yeah 3 gallon dry out a bit faster then 7 but not that much.

Yield is what I'm going for haha and 4 ounces a plant would be nice lol

If you have to ask if those would fit, you are nowhere near getting 4 oz./ plant.
Just a note, you can veg 30 days, and not outgrow a 5 gal. pot.