727 or 904

I,m installing my 408(410)with the 904,I,m having it built to handle anything HP wise.The 410 will be pushing over 500HP and if down the road I want to add some giggle juice(nitrous)I could and the tranny should handle it.New lower 1st gear,Red Racing belts,change drum,manual valve body.The 727 is a great tranny,but is getting harder to find around here.There,s still lots of 904,s kickin around which is good for parts swapping.Also there,s lots of guys racing with the lighter 904 and doing well.Anybody heard of the sprag exploding with the 727?It happens,I guess with loads of HP.My 2 cents(Canadian)which is 2 1/2 (US)LOL