Agreed, 48K is low by most standards, but it sounds like a Motor Home car to me in which case it had plenty of travel time. As to having an original exhaust system, I have to disagree. Not running a car much causes water to build up in the low areas which causes rust out. Not just Honda's but all collector cars have the same problem.
A good way to evaluate the engine being original is Honda's use of Honda Bond (a silicone based sealer) on the engine cases. And the gasket material Honda used for the cam box to head has been red, gray and black. The gasket to the cylinder to case has also been red, gray or black. Making a determination on this is not a sure thing. However a total view of the engine compartment having all the original clamps, hangers, high tension wire to Spark Plug connections, labels, bolts, nuts and screws in place is a good indicator of low mileage cars. Also, wear of interior seats, door panels, carpet and windshield seals in place and not warn or deteriorated to a great degree. But even these items can be damaged from the elements when not stored properly.
So it boils down to documentation, if the paper work, maintenance records, history of ownership, DMV records all indicate a low mileage car then it can be a fair and educated guess that it is a 48K car.
Just my cut -
Bill
> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > Miles > Sent:
> Friday, February 27, 2009 12:39
> AM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> [2cylinderhondas] Re: General question
> The most common reason that the numbers won't match is the engine was
> changed because either it threw a rod through the cases or because
> someone just put a different engine in it from either a sedan or > coupe.
> Sometimes when there is absolutely no engine number on the top > case > it's because the cases were changed, purchased new from Honda and new
> cases are not stamped with a number.
> A car with only 48,000 miles
> should have matching numbers anyway - it's
> pretty low mileage.
> Miles
> --- In
> 2cylinderhondas@ yahoogroups. com
> ,
> "fedweezee"
> wrote:
> > I just
> picked up a 72 az600 (10/71) production date with 48k original > > miles > and i was wondering is it rare to find a coupe with numbers > > matching?
> The engine numbers match the engine numbers on the serial > > number > plate located on the drivers side front. I was told by people > > that > the numbers never match even from the factory. Is this true or
> not???