727 or 904

i had a 904 bolted up to my 318 but when I had it running before i tore into the engine. the thing would quit whenever i put it into gear. so I bolted up the 727 it was just sitting there anyway.
Hindsight. after tearing into the engine, the timing chain was so worn and the cam was so round i figure there was probably nothing wrong with my 904 after all. I'm gonna keep it around for a spare.