Here is what I came up with:
N25: Engine Block Heater
(could also be M25, wide sill moldings)
With a 383 auto it will be a 8 3/4 with either 2.92 or 3.23 gears as a most probable.
I gave up trusting tags after I passed on a rear with a 2.73 open tag on it for $50 and my co-worker bought it and it turned out to be a 3.23 SG.
I hate to break up cars, but this guy apparently has an open title and registering a car with one of those, assuming this isn't rusted out totally underneath, can be a PITA here.