Just from experience I know the 833 will take a ton of abuse , but there are a lot of variables , there is the 23 splineusing the smaller fornt brg , & the 23 spline using the hemi 308 front brg , , the 23 OD using the 308 brg as well but some had fewer splines in the syncro hubs in later years , The OD in my Duster with fulkly spline syncros lived behind 525 HP for years ,. The 18 spimne is even tougher with the heavier input shaft [not that I have ever seen even a 23 spline twist or break ] & the gears are pitched differently for more strenght too & it uses the large 308 brg as well , The Gm guys used to use a special blast sheild in Pro stock & use the 18 spline Mopar in th eearly 70s
I used a built 727 behind a 850 8/71 blown 440 & it lived just fine , & lasted two seasons of racing possibly more , but I saw 1 used behind a blown alcohol 440 with probably 1200-1400 hp & it launched the drum over the grandstands at the track, luckily it missed the driver on the way out the door , I think a Lenco was in order!!