Age Old Question

The 727 is heavier, longer, and stronger. The 904 is lighter and a bit quicker all things being equal. The 904 can be made to hold a 340 or 360. Just do not think you can put your 200,000 mile 904 behind a 340 and expect it to live for very long without at least changing fluid, filter, adjusting the bands, and upping the pressure. Not many parts interchange. That is the short answer.