Transplanting after Flowering Stage has Begun

i am growing in 4 gal pots under a 600 watt system the plant is, from the bottom of the pot to the top of the plant 3.5 feet high and the drain holes are full of roots so i am pretty sure that it is root bound my question is should i transplant into 7 gal grow bags and if i do what are the consequences of transplanting at this late date it has been in flowering stage now for about 8 days but still not showing signs of flowering or even what sex it might be.

I'm looking into the same thing right now... but my ladies are almost done so I'll just wait it out this time and plant my babies in larger pots from the beginning.

8 days of flowering and without showing sings of sex ? definitely man, go for it no doubt.