engine case belly numbers

Identifaction of VIN, case numbers and cylinder heads
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mbskeam
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engine case belly numbers

#1

Post by mbskeam »

Cotten......

was it you that posted about the belly #s being higher than the vin #.
like ...156-8008 vin....56flhxxxx
I recall reading this and cant seem to find it.
and if you did post this , from what source did you come by this info?
thanks

mbskeam



FlatHeadSix
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belly numbers

#2

Post by FlatHeadSix »

Mike,
The best info comes from Bruce Palmers book. Check the thread below about identifying the panhead on ebay.
harley changed the numbering system used by the machine shop after 1947. There is also a little terminology confusion because they refer to the belly numbers as "production" numbers but they also refer to the sequntial number in the vin as a "production" number.

Raw engine cases were given a production number by the machine shop to identify matched cases as they were machined. All cases from 1948 on up had an extra code at the beginning. The first number indicates what engine the cases were intended for, the "1" in the 153-XXXXX means it was being made for a 74 cubic inch FL. The sequential number following the hyphen is just a unique number issued during the machining process. When the engine became part of a complete bike the assembly folks stamped the vin number on the vin pad using a different sequntial production number. Palmer tells us that if the production number on the belly matches the production number in the vin then something is wrong.

The only thing that should match between the belly and the vin is the year.

hope this helps clear it up a little, your numbers appear to be correct.

FlatHeadSix
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Belly number exception

#3

Post by FlatHeadSix »

Mike,
someone posted a belly number pic in the miscellaneous section of the gallery, the production number is pretty clear on one of the cases but appears to be gimped up on the other case. the first 3 digits are not very clear but they appear to be 249- which would indicate that it was produced in 1949 and intended for use as a 61 ci motor.
The pre-1948 belly numbers did not have the engine type code in front of the year.

Here is a pic of the most common exception to belly number-vin number mismatches. This is the bottom of my WL engine, it is pretty clear that this engine went through the machine shop in 1943 but the vin number stamped on the pad is 47WLXXXX. The factory built 88,000 WL's for the army during the war and they probably produced enough spare parts to re-assemble just about all of them. All those surplus parts are what are keeping our old flatheads one the road 60 years later. My '47 probably has a surplus engine on it.

did you leathers dry out yet?
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Guest

#4

Post by Guest »

Is it possible for a 63 to be legit with a right side belly number of 161-xxxx and a left side of 162-xxxx

Thanks

rigidpanman
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#5

Post by rigidpanman »

guest i would say so,i imagine over the years these cases have been mixed and matched so much there`s no way to know.

Guest

I thought Harley had records for '62 and up?

#6

Post by Guest »

Maybe you can call them and have them check that vin, maybe they know the history of the engine. It's worth a shot. I read that on a post from this forum a while back.

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