LA 360 or 5.2 magnum

Yup- I ran down this morning and had a look. It's a original to the truckLA 318. Still a one owner sweety for its age but wish it were a 360. I may not ever use it but it will be too good to throw out and I will be storing it for nothing. It looks like an 8 1/4 rear end in the truck. I thought it would have had a heavier diff than that
Thanks for all the replies
Doug