Are 10 x 2 1/2 rear drums big enough?

I got this project car which came with newly rebuilt 10 x 2 1/2 rear drum brakes. I want to transfer these over to a Dana 60 I will be narrowing. Will they be big enough for a 11.5 second car? I'll have manual front discs and a proportioning valve. I hate to spend more money finding and rebuilding 11x3's but if I really should then I will. Thanks.