Greetings All,

Well, after a day of exploring our new acquisition, the '85 Barth, I ran the VIN since we have no data on the coach and are now on the hunt.
What we discovered about our coach is that, according to the VIN, it had a Diesel "Cummins 6" engine and a AT542 transmission. We have limited paper data on the coach and wondered about the page we found on this tranny. Now, we suspect we have the answer(s).
At some point, we can assume the Cummins and/or transmission either wore out or blew up and a gasser Chevy 454 engine with Turbo Hydro 475 was installed. We have noted a dash panel anomalies (gauges) as well. To do this type of change would be HUGE from motor mounts, fuel feeds and tanks, Genset, etc.
The other assumption is that the Cummins and AT542 were never installed, answering an order change for the 454 engine which leaves the Allison tranny page in the paper work and the dash gauges anomalies still a question.
I checked the VIN against many other sites with the same results.
This link is to the GM Service site for the VINs: https://service.gm.com/dealerworld/vincards/
Select your production year and go from there.
Any thoughts out there?

Thanks.

1985 Barth Regal
30', 454 c.i./TH475
Data tag 8409-3147-30FP-3

Wow! How bizarre is that? Like you, I doubt that the Cummins 6 was ever there… never heard of one on the P37 chassis.

Are you sure the VIN is correct? My plate is located on the center frame in front of the radiator. It might be worth checking to be sure. Another Barth variation mystery! No wonder you had questions about the identity of the transmission, too.

Does your VIN match the correct year? I see the Barth model year was 85 but the production date was 8409 i.e. Sep 84. Sometimes the actual production year of the chassis is up to a year before the Barth build date. Interesting…

Yep...this is bizarre.
Yes-the VIN tag is where it's supposed to be and we both checked it out carefully to make sure there were no mistakes....there were none. It matched the BMV, other documents, and the VIN tag looked original: rivets weren't disturbed, old as dirt, and very factory....we are scratching our heads on this. None of it makes any sense except that maybe the designator letter actually stood for something other than a diesel.....I got this information directly from the GM site, so the mystery deepens.
I do know that the digit in the ninth position serves no purpose. We saw this on another vin for another motorhome.
Yes-Steve, you are absolutely right on when the P frame or cutaway was produced and when the coach was finished and marketed.
Maybe someday the mystery will reveal itself!

One of my good friends is a GM parts wizard who finds stuff when no one else can. He has worked at a GM dealership for over 20 years. I will ask him if he is aware of any P3X chassis with Cummins powerplants. If you want to PM me that VIN I will call him and see if he can shed any light here.

Actually, the ninth number does have a purpose. It is referred to as the "check digit" There is a mathematical process used to combine all the other digits to get a checksum, this sum is divided by 11 and the remainder is the value of the check digit. It is used to be sure the other VIN number digits have not been altered.

The alpha digits are assigned a numeric value. All the digits are then multiplied by another number (referred to as the "weighting") The resulting products are added together to get the checksum. If the checksum/11 does not match the check digit, the VIN is bogus.

That said, even most car dealers don't know how to do the calculation. (The "weighting" values vary depending on the position of the digit) Even if the VIN is bogus, there is a 1 in 11 chance it will match anyway. A halfway smart mathematician can juggle more than one digit to create a new VIN with a checksum that will match exactly.

I have all the formulas for modulus 10 (most common). Modulus 10 is used for all the credit cards. It is a mystery to most computer programmers but is great to catch input errors.

6.2 and 6.5 were used on the p-3x chassis, but the weight of the cummins is way to high. There were some front diesels, but not on the GM chassis. At least I never heard of one and been around the industry since 1978.

Airstream made some Isuzu powered coaches on the GM chassis. Those were the motor homes that looked like a airstream.