a friend of mine just had his 53 216 rebuilt. Runs like a champ. Had the block boiled out, etc. He and another guy did the work. But getting a shop to do it is not bad idea either. Just look to see if the shop is clean or if there is a lot of junk sitting around. My buddy paid about $2200 for the parts and machine work, but he did the labor.
He exchanged the rods for machined rods to except inserts. I think that is a good improvement for the older engine. all of my trucks have the older low pressure engines(3 216's, 1 235) they all run great and have plenty of power for the original driveline.
I would keep it unless you want to pay for a later pressure engine and then also pay the rebuild fees as well.
