I agree...not the strongest rear end around as they still use the old ball-bearings, but on the bright side...they dont use c-clips either.

As far as being strong enough for the 454, it all depends. They were being used in hot rods with Olds Rocket 88s back in the day and up to 1962 in the Corvette. If your using it in a unibody car like a Camaro you will probably bend a trailing arm on the chassis before you break the rear end. BTW...Pontiac used them in GTOs with the big blocks.

Oh and third members are differentials that can be taken off the axle in one piece instead of the dif (ring, pinion, carrier, bearings) being bolted directly to the axle like the late model model mustangs.