Here's a similar build but with a 400 instead.
140,000 mile short block out of a 1974 Polara wagon. Lots of camper towing during it's life, big ridge at the tops of the bores.
Ridge ream it to get it apart.
PAW re-ring kit in hand, block and crank get hot tanked. Block gets a dingleberry hone, crank gets a quick polish. New freeze plugs and cam bearings.
Found some 516's, valve job done, install 1.74 exhaust valves. Very minor bowl blend, mill .030, mp933 springs.
Reassemble with new timing set, oil pump, rings, bearings, gaskets.
Mp 484 cam, Holley SD intake, new 650DP carb, recurved stock dist, 1 3/4 headers.

Installed into a 71 Charger R/T, 4.10 gears, Dynamic 10" converter......went 13.50's @ 105, 3950lbs. This was in about 1986 or 87. Owner ran it like that until 2004 when I built an E headed 446 to replace it.
He sold the 400, still running fine after all those years.

Edit: oops..... I got this build mixed up with another low buck 400 I did during that same time. This motor didn't start out as the well used piece out of the Polara wagon. The core for this one came out of like a 72 or 73 Charger that had gotten replaced by a 440. This one was sitting in his garage for a couple of years and the guy was tired of tripping over it and was ready for it to find a new home. It wasnt really all that used up when I got it...... It was worth the $50 I gave him for it.
The rest of the story is correct.

The one that came out of the Polara is a better story though.