Ray,
Looking at some online figures, the standard Healey rear end weighs 165 lbs (not sure whether that's with brakes). The Explorer 8.8 with brakes weighs 175 lbs. Sounds doable if someone was considering a 3.55 and disc brake swap for their Healey. I guess it would depend on how much the extra work to adapt wire wheel hubs and throw in the cost of a new driveshaft as well. One advantage to the Explorer is the parking brake issue would already have been worked out. Obviously, it's not for everyone, but if you're the type not offended by a Smitty's 5 spd, this wouldn't bother you too much.