You won't need any rods or bearings. The thing to do is to pull the head, and inspect a few things:
1) the timing cover back half will be melted right in the middle at the block/head split, if the engine got hot enough to damage things. If it's melted, the engine could be worse off and might need a whole lower end. Oddly enough the head is likely to survive. This is the indicator for how serious the overheat was. If the guy drove it until it stopped running, then it's probably a bad one.

2) The #1 cylinder bore may be scored, the piston may be melted, and the rings may be damaged. In this case the block is probably out-of-round on bore #1. The only fix is to have the block "sleeved" and pistons replaced, matched to the new bore, or just get another long block (cheaper, and readily available)
If theres any raised metal on the top rim of the piston, or the head is scored, or the cylinder has vertical scratches, it needs more work and at least a lower-end from a Turbo is required. Honestly, these engines are cheap, $400 retail at the junkyards. You can't rebuild one for that price. That'll take care of what this car needs and a used engine such as this will be as tight as anything you'll pay a machine shop for.

Good luck, it'll be a nice car when it's done. Save the money you'd spend on the head gasket and machine work.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 229K, 88 744GLE- 218K, 82 245T-181K Also responsible for the care and feeding of: 88 745GLE, 231K, 87 244DL, 239K, 88 245DL, 246K