741 Center Section question?

IMO, most of the 3.91 gear sets came in trucks/vans. I find them mostly in trucks/vans. Think how tough it is to find an axle packaged A body car. There just aren't a lot of them out there.

741's can handle 500-550hp as long as they are put together well. The ring gear and drivers side cap is the weak point, NOT, the pinion bearing diameter that gets tossed around.

As far as the SG going away in 2-3 trips to the track, they were likely pretty worn before you got there.