741's handle a bunch more than a 318 with a cam. I ran 440-6/hemi 4 speed cars with 741 cases. The weak 741 thing is total BS.
The ring gears are the weak point and they ALL use the same ring gear for each respective ratio.
741's doesn't have any stress risers on the pinion, unlike the 742 and 489 pinions.
Unfortunately it's like that commercial on TV... It was on the internet so it must be true... BLAH!!! Make me barf.