YES!
With out question yes. Horsepower is a good increase but torque is the name of the game. My 347 makes 310 hp, it is a really mild build but even with that it makes 370 ft torque through an automatic. I have seen 347 make 350/360 hp and 420/430 ft tq with no problem.
If I had to do it all over again I would go 393 myself and that is what I am going to do next. I'll be a member of the 500/500 club.
Don't let anyone tell you about rod ratio, oiling pin, yadda, yadda, yadda about the 347. The rod ratio is better in a 347 than a 454 Chevy. I have had mine for three plus years and not a single problem. It is like anything else use quality parts and you will get quality service out of the engine.