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MG MGA - Body# Deciphering...

I cant seem to break down my body number. The plate is missing and the registration has 1957 MGA HDB4318288 on it. Is there a mistake? The car was originally blue


The Registration is interesting.

The H stands for an MGA.
The D stands for Roadster (M would be for the coupe).
The B is non standard. If the original colour was blue the letter would be D or possibly L.
The 4 stands for LHD North American Market.
The 3 stands for Cellulose paint.
18288 is the car/chassis number. This number would suggest the car was built about July 1956. Earlier than your 1957.

Steve Gyles

The only thing I can still find on the car is the body tag which says B 6040. I would like to get the registration corrected if it is wrong. Thanks for the help on the deciphering!!!

The plot thickens.

According to Clausager's Original MGA the B prefix on the body was allocated to the 1600/MkII/late Twin Cams. The numbers were in the range 101 to approx 40600.

It would seem that your chassis has inherited a newer body at some stage.

The actual chassis number is often visible, stamped into the chassis on a crossmember in the right hand cockpit compartment. I think I have a photo of it somewhere. I will post it if I can find it.

Steve Gyles


Picture attached. It is the right hand number that is the chassis number.

The left hand number is the frame number. That has a different meaning and was used by the welding teams.


Steve Gyles

If you can not find the VIN stamped on the right hand section of the frame, you'll have to assume that the registration has the correct VIN. No records were kept of what numbered bodies were placed on what vehicles.
David Werblow

Thanks for all you help. I cant seem to find the number and assume it was sandblasted off during restoration. I remember the plate was rusty and fell off before restoration and have lost it since. I guess i'll never know the true year!

The chassis number was also (not always) stamped on the left hand lower front dog leg..there has been much comment about this, with some saying that this was for CKD cars only, but mine was an early 1500 US export, and had the number stamped there..I couldn't find any evidence of numbers on the cross rails. Just have a good look around that front LH area.
Gary Lock

Clausager does not list B for color but Moss does. Moss lists B as light grey, or dove gray. Dove grey was a 1600 color. A blue 56 roadster would be a L code. Your car appears to be a 1956 serial #. Many states would register the car to the year it was first registered not the year produced. Your car was probably first registered in 1957. It must have sat around on a dealers lot for a few months at least.
R J Brown

Your VIN is the number starting with:HDB The body No. B6040 is the number only for the body. The body no. of my car is B7013. It is the body from a late '59 1600 (disc brakes-front only) w/disc wheels but definately NOT a twin cam. The VIN I'm using is from an earlier '59, a 1500: HDK435_ _ _ _. In theory the K stands for light red. but I could find no sign of that anywhere on the car!
David Werblow

To Steve Gyles,
referring to your email and photo of the front gearbox rail numbers, if there is a number on the passenger rail (of an original right hand drive car) are you saying this is not the chassis number but rather I would find the chassis number on the drivers side rail? Could the builders have reversed this on left hand drive cars?

Gary, yes one of my 3 chassis has the dogleg stamp but not the other 2, one of which was a private english import from the early 1960s
Mark Mathiesen


The MGA 50th Anniversary book has the whole story about the various numbers stamped in the frame.

I will put the article in a PDF file tonight so you can have a read. In summary, the left hand frame number was a sequencial number series of MGA frames being welded up, regardless of whether they were for Roadsters, Coupes or Twin Cams. The number always had a letter prefix, defining which welding team built the chassis. The right hand number was the standard chassis number as shown on the identification plate on the shelf in the engine compartment. The author of the article has done some research and there appears to be a loose relationship between the 2 sets of numbers

Both numbers are visible on my car, but the quality of the stamping is nothing like as good as shown in the photo I attached above. My frame number is K45126 and my chassis number is 55600, the difference between the two being 10,434. Bearing in mind that the first MGA production chassis was number 10101, that puts my frame number 333 apart from the chassis number. The difference probably being the number of Coupes that had been built before my car on 27 August 1958.

Steve Gyles


I think I got the last bit wrong about the reason for the 333 variance. I need to reread the article.

Steve Gyles

I've always been told that there is no real correlation between chassis no and body no. They switched to the B prefix with the introduction of the 1600. The bodies were built in blocks of 1000 alternating roadster and coupe and assigned to a chassis when required. It is unusual for the numbers to differ by more than a few thousand (possibly with the 10101 added on)

My early 56 Roadster has a body with a B so there must have been some marriage of cars before I got it.

I also saw an imported car (from South Africa) that had been registered using the body number. The records had been used to generate the rest of the letters which meant that it the Tyrolite Blue RHD car appeared to be a Red American LHD car.

Dan Smithers

The chassis number stamping on the left front lower dogleg was not done by the Abingdon factory. It is found on some Australian MGA's mainly CKD, but also the occasional CBU car. It was probably a requirement of the Registration authorities in some, but not all Australian States.
To Gary Lock, which year was your 1500 (US export)actually imported into Australia and what is the chassis number?
To Mark, no the LH and RH numbers are never reversed. The article in the MGA 50th Anniversary Yearbook on "MGA Archaeology-Chassis Identification" by Robin Barker is a brillant piece of research, well worth a read, and explains all in detail.

Garry Kemm

I have put the Chassis Identification document on my website: Scroll down to item 15.

The author, Robin Barker, also makes reference to cars exported in CKD to Australia, Ireland, Mexico, Netherlands, Philippines and South Africa.

He is also after more evidence for his statistical analysis, so if anyone has both the frame and chassis numbers please email to

Steve Gyles

This thread was discussed between 22/07/2007 and 25/07/2007

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