I figured I'd use it once at 105K miles on my '87 since it was on sale and not much more per quart than goold 'ol dinoblood.
What a mistake, it seeped past the front crank seal and slung everythwere. Now the damage is done, still seeps a little back on regular oil awaiting a new seal.
Oh, and the car is currently sitting in front of my house with no belt because it was pouring rain last night, wife had no choice and went through a big puddle, well oil on belt plus water = bye bye belt
So my opinions of the stuff on a older engine aren't too high. Maybe, just maybe if I'm going to keep the car a while longer and replace all the seals, then, yeah I'd probably use it then, but not on the old seals.