The 904 vs 727 debate is almost akin to the slant 6 vs the 318... It takes a lot more parts and a lot more money to build a slant into the power a 318 makes stock. Same goes for the 904 stock they can't take the same abuse as 727 stock and survive.
We might as well if it was original to the car and did not have to modify things to make it fit...if it had a bolt in sprag and we needed the extra weight and beef for large horsepower application.