I am aware that matching belly numbers are important when buying panhead and earlier models. I am considering getting a 1970's shovelhead for the first time and am wondering if this is still relevant since they began to match the frame and engine vin for id purposes. What's the scoop with '70's bikes in this regard? The bike I'm looking at is 1974 fxe model

 

bottom numbers were stamped by the guy who matched the case halfs in machining so they are a matched pair after line honing and bushing centers

I don't know when they stopped matching the bottom numbers with the chassis ID numbers but that was originally the way it was done - my 1926 JD the bottom numbers match the chassis ID number - I have never seen even a knucklehead top and bottom match but I guess it was possible\

so many things went on during all the years we look at the casted in date codes inside the case halfs, to see if the year of the blocks date code is correct for the stamped year on the engine

 

I took a look at my case belly there's some numbers, I have a 77 frame and motor match, what I see the first few numbers are 1 77 so I assume it's good...

 

Always good to get an engine with matching BNs, regardless of Shovel, Pan, etc, because if the BNs are authentic then you’ll know the cases were originally machined together as a matching pair. For a 1974 Shovel the BNs may be formatted as per the following example: 174-1234(5). Something to check is the type of 4s because H-D used at least two of them in 1974 Shovel BNs. Both were an open-back style but one was taller than the other. If you post photos we can give you an opinion if you like.

A 1974 FXE would originally be 74ci and the VIN should begin with 9D. Full VIN should be formatted as per the following example: 9D12345H4. I expect the 4 will not be an open-back type; instead I imagine it will be a certain closed-top style. If you post photos we can give you an opinion and if you’re concerned about the VIN being on the internet then you could cover a few sequence characters. At each end of the VIN I would expect to find a five-pointed star.

Stamped on top of each case near the rear engine mounting bolts you may find the letter H. If so I would expect it to be sans serif and capital.

And look at the back of the R-H case near the oil pump. Sometimes you’ll find ID stamped there. I’ve seen it used for 1975-later but I am not sure if it was there for 1974. You’d be looking for something similar to A123. If any ID is present, also check the left case in a corresponding position. Sometimes this ID is near the BNs but again I am not sure if it was used for 1974.

BTW, as of 1975 models there was a change to the BN format. For example, the left BN would be in three portions similar to 175 012 123. Also as of 1975 Shovels the R-H BN wasn’t under the case; instead it was stamped inside the gear compartment.
Eric

 

FYI, not sure how many years MoCo did this but my 75 FXE had the right belly number located inside the right case. The bottom of the right case (where the belly number would be) was blank. On the road right now but if need be I can post up a pic when I am back home tomorrow afternoon.

 

The R-H BN for Shovels was stamped inside the gear compartment for at least 1975–80 and 1982.

For 1979 Shovels, not only was the R-H BN stamped inside the gear compartment but it was also sometimes stamped on top of the case. However, it was on top of the case for a short period only and it was due to The 1979 Exception.
Eric

 

Thanks for all of the helpful information, guys--much appreciated.